Editorial

4 pages, 319 KiB

Open AccessEditorial

Special Issue Titled “10th Anniversary of Processes: Recent Advances in Environmental and Green Processes”

by Antoni Sánchez

Processes 2024, 12(3), 552; https://doi.org/10.3390/pr12030552 - 12 Mar 2024

Viewed by 457

In 2019, one of the Editorial Staff of the MDPI journal Processes, sent me an email informing me that I was being invited to join the Editorial Board of the journal, a proposal that I accepted [...] Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

Research

Jump to: Editorial, Review, Other

27 pages, 12967 KiB

Open AccessArticle

Preparation of PVA/SA-FMB Microspheres and Their Adsorption of Cr(VI) in Aqueous Solution

by Jinlong Zuo, Jin Ren, Liming Jiang, Chong Tan, Junsheng Li, Zhi Xia and Wei Wang

Processes 2024, 12(3), 443; https://doi.org/10.3390/pr12030443 - 22 Feb 2024

Viewed by 513

Abstract

Biochar, a carbon-dense material known for its substantial specific surface area, remarkable porosity, diversity of functional groups, and cost-effective production, has garnered widespread acclaim as a premier adsorbent for the elimination of heavy metal ions and organic contaminants. Nevertheless, the application of powdered [...] Read more.

Biochar, a carbon-dense material known for its substantial specific surface area, remarkable porosity, diversity of functional groups, and cost-effective production, has garnered widespread acclaim as a premier adsorbent for the elimination of heavy metal ions and organic contaminants. Nevertheless, the application of powdered biochar is hindered by the challenges associated with its separation from aqueous solutions, and without appropriate management, it risks becoming hazardous waste. To facilitate its use as an immobilization medium, biochar necessitates modification. In this investigation, sodium alginate, celebrated for its superior gelation capabilities, was amalgamated with polyvinyl alcohol to bolster mechanical robustness, thereby embedding biochar to formulate sodium alginate biochar microspheres (PVA/SA-FMB). A meticulously designed response surface methodology experiment was employed to ascertain the optimal synthesis conditions for PVA/SA-FMB. Characterization outcomes unveiled a highly developed surface abundant in functional groups and confirmed the successful incorporation of iron ions. Adsorption trials revealed that at a temperature of 25 °C and a pH of 2, the adsorption capacity of PVA/SA-FMB for Cr(VI) was 13.7 mg/g within the initial 30 min, reaching an equilibrium capacity of 26.03 mg/g after 1440 min. Notably, the material sustained a Cr(VI) removal efficiency exceeding 90% across five cycles, underscoring its rapid and effective Cr(VI) eradication performance. Kinetic and isothermal adsorption analyses suggested that the adsorption of Cr(VI) adheres to a pseudo-second-order kinetic model and the Freundlich isotherm, indicative of monolayer adsorption dominated by reaction mechanisms. X-ray photoelectron spectroscopy (XPS) analysis inferred that the adsorption mechanism predominantly encompasses electrostatic attraction, redox processes, and complex formation. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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26 pages, 4558 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modelling of Drinking Water Recarbonization in Fluidized Bed Reactor

by Ján Derco, Nikola Šoltýsová, Tomáš Kurák, Anna Vajíčeková and Jozef Dudáš

Processes 2023, 11(11), 3209; https://doi.org/10.3390/pr11113209 - 10 Nov 2023

Viewed by 739

Abstract

Calcium and magnesium are important not only for human health but also for reducing problems related to the corrosive and aggressive effects of soft water on drinking water distribution materials. Experimental and mathematical modeling of the recarbonization process aimed at increasing the content [...] Read more.

Calcium and magnesium are important not only for human health but also for reducing problems related to the corrosive and aggressive effects of soft water on drinking water distribution materials. Experimental and mathematical modeling of the recarbonization process aimed at increasing the content of these biogenic elements in water was carried out using the novelty of continuous laboratory- and pilot-scale fluidized bed reactors. A methodology for scaling-up the modeled system was extended with mathematical modeling. Water remineralization was performed using half-calcined dolomite (HCD) and CO₂. The influence of operating conditions, i.e., Q(CO₂), freshwater inflow, and HCD dose, on quality indicators of treated drinking water (c(Ca²⁺), c(Mg²⁺), c(Ca²⁺ + Mg²⁺) and Ca/Mg) was studied. Results show that the Mg²⁺ concentration is more significantly affected by the amount of HCD in the system and the flow of CO₂, while the effect of freshwater inflow is less significant. At constant CO₂ flow, the Ca²⁺ content decreases and the Mg²⁺ content increases as the tap water inflow increases, which results in a decrease in the Ca/Mg molar ratio. However, the Ca/Mg ratio can be effectively controlled by adding an appropriate amount of HCD at certain time intervals. Overproduction of ions is easily controlled by the CO₂ flow. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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12 pages, 3310 KiB

Open AccessFeature PaperArticle

Production of High-Porosity Biochar from Rice Husk by the Microwave Pyrolysis Process

by Li-An Kuo, Wen-Tien Tsai, Ru-Yuan Yang and Jen-Hsiung Tsai

Processes 2023, 11(11), 3119; https://doi.org/10.3390/pr11113119 - 31 Oct 2023

Cited by 2 | Viewed by 1210

Abstract

This study focused on the highly efficient pyrolysis of rice husk (RH) for producing high-porosity biochar at above 450 °C under various microwave output powers (300–1000 W) and residence times (5–15 min). The findings showed that the maximal calorific value (i.e., 19.89 MJ/kg) [...] Read more.

This study focused on the highly efficient pyrolysis of rice husk (RH) for producing high-porosity biochar at above 450 °C under various microwave output powers (300–1000 W) and residence times (5–15 min). The findings showed that the maximal calorific value (i.e., 19.89 MJ/kg) can be obtained at the mildest microwave conditions of 300 W when holding for 5 min, giving a moderate enhancement factor (117.4%, or the ratio of 19.89 MJ/kg to 16.94 MJ/kg). However, the physical properties (i.e., surface area, pore volume, and pore size distribution) of the RH-based biochar products significantly increased as the microwave output power increased from 300 to 1000 W, but they declined at longer residence times of 5 min to 15 min when applying a microwave output power of 1000 W. In this work, it was concluded that the optimal microwave pyrolysis conditions for producing high-porosity biochar should be operated at 1000 W, holding for 5 min. The maximal pore properties (i.e., BET surface area of 172.04 m²/g and total pore volume of 0.1229 cm³/g) can be achieved in the resulting biochar products with both the microporous and the mesoporous features. On the other hand, the chemical characteristics of the RH-based biochar products were analyzed by using Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDS), displaying some functional complexes containing carbon–oxygen (C–O), carbon–hydrogen (C–H), and silicon–oxygen (Si–O) bonds on the surface of the RH-based biochar. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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9 pages, 694 KiB

Open AccessArticle

French Fries’ Color and Frying Process in Relation to Used Plant Oils

by Bojan Antonic, Dani Dordevic, Hana Buchtova, Bohuslava Tremlova, Simona Dordevic and Ivan Kushkevych

Processes 2023, 11(10), 2839; https://doi.org/10.3390/pr11102839 - 27 Sep 2023

Cited by 1 | Viewed by 1097

Abstract

Fast-food establishments today often sell fried food without proper control over the frying oil, and french fries are a prime example. Neglecting the maintenance of frying oil can lead to decreased taste, health concerns, and operational inefficiencies. The following plant oils were used [...] Read more.

Fast-food establishments today often sell fried food without proper control over the frying oil, and french fries are a prime example. Neglecting the maintenance of frying oil can lead to decreased taste, health concerns, and operational inefficiencies. The following plant oils were used in the frying process: rapeseed, sunflower, and palm oil. The degree of frying was measured by the total polar meter (TPM), until the achievement of 24%. To accurately assess the color characteristics of the french fry samples, Minolta CM 2600d color measurement instrument was used. Statistically significant differences were observed between some color parameters (L, a, b, C, and h) and TPM values. The following correlations were observed: 0.530 was obtained for TPM and h (hue angle) in french fries fried in palm oil; negative correlation (−0.214) between TPM and L (lightness) was obtained in french fries fried in rapeseed oil. While we have observed certain correlations from our experimental data, it is important to note that the color of french fries may not be the sole determinant of fried oil quality. Other external factors, such as temperature, chemical composition, and potato cultivar, can also significantly influence the color of french fries. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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17 pages, 2384 KiB

Open AccessArticle

A Comparative Study on the Bioavailability and Soil-to-Plant Transfer Factors of Potentially Toxic Element Contamination in Agricultural Soils and Their Impacts: A Case Study of Dense Farmland in the Western Region of Saudi Arabia

by Basma G. Alhogbi, Shroog A. Al-Ansari and Mohammed S. El-Shahawi

Processes 2023, 11(9), 2515; https://doi.org/10.3390/pr11092515 - 22 Aug 2023

Cited by 2 | Viewed by 1104

Abstract

Soil and aquatic pollution by heavy metal (Pb, Cr, Cu, Fe, Zn, and Ni) ions has become one of the prime problems worldwide. Thus, the purpose of the current study is to conduct hydrogeological research and quantify the main trace metals in the [...] Read more.

Soil and aquatic pollution by heavy metal (Pb, Cr, Cu, Fe, Zn, and Ni) ions has become one of the prime problems worldwide. Thus, the purpose of the current study is to conduct hydrogeological research and quantify the main trace metals in the edible vegetables, soil, irrigation water, pesticides, and fertilizers in the farmland near Jeddah city, Saudi Arabia. Samples of soil, water, and plants such as coriander (Coriandrum sativum), dill (Anethum graveolens), parsley (Petroselinum crispum), and arugula (Eruca sativa) were collected, acid-digested, and analyzed using an inductively coupled plasma–optical emission spectrometer (ICP–OES). The levels of the elements in soil were determined in the order of Fe > Zn > Cu > Cr > Ni > Pb, whereas the sequence in plants was Fe > Cr > Zn > Pb> Ni > Cu, and in water, the order was Pb > Fe > Cu > Zn> Ni = Cr. In soil, the levels of Fe, Cr, and Pb were higher than the recommended values set by the World Health Organization (WHO) and the Food Administration Organization (FAO). In soil, Pb and Zn uptake increased with an increase in the availability of both elements, whereas in plants, Zn and Pb uptake occurs primarily through the plant roots, and some specific proteins facilitate metal transport and movement across the membrane. In soil, the root cell walls first bind to metal ions, which are taken up across the plasma membrane. The levels of the investigated elements in water and vegetables samples were below the permissible limits set by the FAO and within the allowable limits in the available pesticides and fertilizers. The transfer factor (TF) of metal absorption from soil to plant (TF_soil-plant) and from irrigated water to plant (TF_water-plant) in the study area was determined, followed by correlation and statistical treatment according to the date. The TF values were used to assess the metal levels in collected plant, soil, and water samples. The computed values of TF implied that plant leaves and soil were safe from the risk of heavy metals. Water irrigation causes heavy metal accumulation in soil and vegetables, with varying concentrations. The results of this study revealed no abnormal metal accumulation due to irrigation and no health risks to consumers. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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19 pages, 5002 KiB

Open AccessArticle

Modelling the Effect of Water Removal by Reverse Osmosis on the Distillation of Mixtures of Short-Chain Organic Acids from Anaerobic Fermentation

by Serena Simonetti and Davide Dionisi

Processes 2023, 11(8), 2362; https://doi.org/10.3390/pr11082362 - 05 Aug 2023

Cited by 1 | Viewed by 1232

Abstract

Anaerobic fermentation (AF) to produce sustainable short-chain organic acids (SCOAs) has found no commercial application so far. This is due to several limitations, including the high energy consumption of the SCOAs’ separation from water by distillation. This study used AspenPlus simulations to investigate [...] Read more.

Anaerobic fermentation (AF) to produce sustainable short-chain organic acids (SCOAs) has found no commercial application so far. This is due to several limitations, including the high energy consumption of the SCOAs’ separation from water by distillation. This study used AspenPlus simulations to investigate the benefits of reverse osmosis (RO) to remove water and concentrate the SCOAs from AF before their separation by distillation. The effect of RO on distillation reflux ratio, heat energy requirements, column diameter and equipment costs was simulated for the processing of model SCOA-containing streams, representing AF effluents. A total of 90 simulations were carried out, investigating three different SCOA compositions, corresponding to different ratios of lactic, acetic and propionic acids, three different concentrations of the total SCOAs (10, 50, 100 g/kg in the stream entering RO) and different extents of water removal by RO. RO brought a reduction in the distillation reboilers’ duty of up to more than 90%, with a reduction of column diameter of up to more than 70%. The total energy consumption, equipment cost and NPV (net present value) of the RO plus distillation process were in all cases more favourable than for the process without membranes. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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12 pages, 978 KiB

Open AccessArticle

Harnessing Digestate Potential: Impact of Biochar and Reagent Addition on Biomethane Production in Anaerobic Digestion Systems

by Alaa Salma, Nur Maisarah Binti Faeruz, Lydia Fryda and Hayet Djelal

Processes 2023, 11(8), 2284; https://doi.org/10.3390/pr11082284 - 29 Jul 2023

Cited by 1 | Viewed by 755

Abstract

This article reports on an experiment that aimed to investigate the effects of digestate and cosubstrate input with varying biochar concentrations on methane production in anaerobic digestion processes. The findings revealed distinct trends in methane production among the substrates. Further investigations were conducted [...] Read more.

This article reports on an experiment that aimed to investigate the effects of digestate and cosubstrate input with varying biochar concentrations on methane production in anaerobic digestion processes. The findings revealed distinct trends in methane production among the substrates. Further investigations were conducted to evaluate the effects of different types of biochars on biomethane production from raw cattle manure digestate. Four conditions were tested: one raw digestate condition and three digestate conditions containing 1% of a different biochar type to one another. BC1 (PEFC-certified spruce BC) and BC2 (oak wood BC) showed promising results in enhancing biomethane production. About 884.23 NmL of methane was produced, with a yield and productivity of 22.80 NmL.g⁻¹ and 1.62 NmL.g⁻¹.day⁻¹ with BC1. However, BC3 (cow and chicken manure digestate BC) demonstrated lower biomethane production compared to raw digestate. Additionally, the study explored the effects of adding reagents to digestate. Hematite and iron chloride salt did not show any positive effects on biomethane production when biochar was introduced, while activated carbon powder significantly improved biomethane production rates by approximately 11.18%. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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13 pages, 2462 KiB

Open AccessArticle

Complex Agent for Phosphate Sequestration from Digested Sludge Liquor: Performances and Economic Cost Analysis

by Shi Yan, Li Nie, Juan Ren, Wei Wang, Jingtao Xu, Ning Wang and Qian Zhao

Processes 2023, 11(7), 2050; https://doi.org/10.3390/pr11072050 - 09 Jul 2023

Viewed by 923

Abstract

Phosphorus (P) management in the “water-energy-resource-nexus” in wastewater treatment plants (WWTPs) remains a longstanding challenge. P adsorption from the P-enriched digested sludge liquor (DSL) is a comparatively more practical and economically viable approach for P recovery in WWTPs. However, high concentrations of impurities [...] Read more.

Phosphorus (P) management in the “water-energy-resource-nexus” in wastewater treatment plants (WWTPs) remains a longstanding challenge. P adsorption from the P-enriched digested sludge liquor (DSL) is a comparatively more practical and economically viable approach for P recovery in WWTPs. However, high concentrations of impurities in DSL might pose a negative and interferential effect on P adsorption, hindering the application of sorbents or precipitation methods. Given such a situation, highly efficient and cost-effective sorbent towards P reclamation from DSL is highly needed. Therefore, this study aims to develop a novel complex agent containing aluminum coagulant and superparamagnetic nano-sorbent (SNS) that can be used in magnetic seeding coagulation for P recovery. The complex agents with different PACl: SNS ratios showed varied turbidity removal rates and P recovery efficiencies and the optimal ratio was 15 mg PACl: 15 g SNS. PAC and SNS showed significant interaction because PAC could enhance P adsorption by shielding the interferential effect of colloidal impurities. In addition, the complex is highly regenerative, with turbidity and P removal rate stably maintained at 70–80% after 10 adsorption/regeneration cycles. The cost–benefit analysis of the dosing complex agent showed a dosing cost of 0.154 EUR/m3, admittedly much higher than the conventional magnetic seeding coagulation, which could probably be covered by the profit if the expensive and rare P product is reclaimed. This work indicated that the complex agent was superior due to its high adsorption capacity, easy separation, and repeated dosing, and therefore had the potential for P recovery from DSL. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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15 pages, 4029 KiB

Open AccessArticle

Determination of Soil Agricultural Aptitude for Sugar Cane Production in Vertisols with Machine Learning

by Ofelia Landeta-Escamilla, Alejandro Alvarado-Lassman, Oscar Osvaldo Sandoval-González, José de Jesús Agustín Flores-Cuautle, Erik Samuel Rosas-Mendoza, Albino Martínez-Sibaja, Norma Alejandra Vallejo Cantú and Juan Manuel Méndez Contreras

Processes 2023, 11(7), 1985; https://doi.org/10.3390/pr11071985 - 30 Jun 2023

Viewed by 1170

Abstract

Sugarcane is one of the main agro-industrial products consumed worldwide, and, therefore, the use of suitable soils is a key factor to maximize its production. As a result, the need to evaluate soil matrices, including many physical, chemical, and biological parameters, to determine [...] Read more.

Sugarcane is one of the main agro-industrial products consumed worldwide, and, therefore, the use of suitable soils is a key factor to maximize its production. As a result, the need to evaluate soil matrices, including many physical, chemical, and biological parameters, to determine the soil’s aptitude for growing food crops increases. Machine learning techniques were used to perform an in-depth analysis of the physicochemical indicators of vertisol-type soils used in sugarcane production. The importance of the relationship between each of the indicators was studied. Furthermore, and the main objective of the present work, was the determination of the minimum number of the most important physicochemical indicators necessary to evaluate the agricultural suitability of the soils, with a view to reducing the number of analyses in terms of physicochemical indicators required for the evaluation. The results obtained relating to the estimation of agricultural capability using different numbers of parameters showed accuracy results of up to 91% when implementing three parameters: Potassium (K), Calcium (Ca) and Cation Exchange Capacity (CEC). The reported results, relating to the estimation of the physicochemical parameters, indicated that it was possible to estimate eleven physicochemical parameters with an average accuracy of 73% using only the data of K, Ca and CEC as input parameters in the Machine Learning models. Knowledge of these three parameters enables determination of the values of soil potential in regard to Hydrogen (pH), organic matter (OM), Phosphorus (P), Magnesium (Mg), Sulfur (S), Boron (B), Copper (Cu), Manganese (Mn), and Zinc (Zn), the Calcium/Magnesium ratio (Ca/Mg), and also the texture of the soil. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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18 pages, 4880 KiB

Open AccessArticle

Removal of Organic Contaminants in Gas-to-Liquid (GTL) Process Water Using Adsorption on Activated Carbon Fibers (ACFs)

by Roghayeh Yousef, Hazim Qiblawey and Muftah H. El-Naas

Processes 2023, 11(7), 1932; https://doi.org/10.3390/pr11071932 - 27 Jun 2023

Cited by 1 | Viewed by 879

Abstract

Gas-To-Liquid (GTL) processing involves the conversion of natural gas to liquid hydrocarbons that are widely used in the chemical industry. In this process, the Fischer–Tropsch (F-T) approach is utilized and, as a result, wastewater is produced as a by-product. This wastewater commonly contains [...] Read more.

Gas-To-Liquid (GTL) processing involves the conversion of natural gas to liquid hydrocarbons that are widely used in the chemical industry. In this process, the Fischer–Tropsch (F-T) approach is utilized and, as a result, wastewater is produced as a by-product. This wastewater commonly contains alcohols and acids as contaminants. Prior to discharge, the treatment of this wastewater is essential, and biological treatment is the common approach. However, this approach is not cost effective and poses various waste-related issues. Due to this, there is a need for a cost-effective treatment method. This study evaluated the adsorption performance of activated carbon fibers (ACFs) for the treatment of GTL wastewater. The ACF in this study exhibited a surface area of 1232.2 m²/g, which provided a significant area for the adsorption to take place. Response surface methodology (RSM) under central composite design was used to assess the effect of GTL wastewater’s pH, initial concentration and dosage on the ACF adsorption performance and optimize its uptake capacity. It was observed that ACF was vitally affected by the three studied factors (pH, initial concentration and dosage), where optimum conditions were found to be at a pH of 3, 1673 mg/L initial concentration and 0.03 g of dosage, with an optimum uptake of 250 mg/L. Kinetics and isotherm models were utilized to fit the adsorption data. From this analysis, it was found that adsorption was best described using the pseudo-second order and Freundlich models, respectively. The resilience of ACF was shown in this study through conducting a regeneration analysis, as the results showed high regeneration efficiency (~86%) under acidic conditions. The results obtained from this study show the potential of using ACF under acidic conditions for the treatment of industrial GTL wastewater. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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13 pages, 4991 KiB

Open AccessFeature PaperArticle

Development of Geopolymer Mortars Using Air-Cooled Blast Furnace Slag and Biomass Bottom Ashes as Fine Aggregates

by Yolanda Luna-Galiano, Carlos Leiva Fernández, Rosario Villegas Sánchez and Constantino Fernández-Pereira

Processes 2023, 11(6), 1597; https://doi.org/10.3390/pr11061597 - 23 May 2023

Cited by 4 | Viewed by 1212

Abstract

The aim of this study is to compare the mechanical and physical properties of different geopolymer mortars made with granulated blast furnace slag as a geopolymer source material, NaOH (8 M) as the activating solution, and three different types of fine aggregates (air-cooled [...] Read more.

The aim of this study is to compare the mechanical and physical properties of different geopolymer mortars made with granulated blast furnace slag as a geopolymer source material, NaOH (8 M) as the activating solution, and three different types of fine aggregates (air-cooled blast furnace slag, biomass bottom ashes, and silica sand). The samples were made with an aggregate/geopolymer ratio of 3/1, and physical (density and mercury intrusion porosimetry), mechanical (compressive and flexural strength), and acid attack resistance were determined. When air-cooled blast furnace slag is used, the mechanical and acid attack properties are improved compared with silica sand and biomass bottom ashes because of the existence of amorphous phases in this slag, which increase the geopolymer reaction rate despite the particle size being higher than other aggregates. It can be highlighted that the use of ACBFS as a fine aggregate in geopolymer mortars produces better properties than in cement Portland mortar. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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10 pages, 2448 KiB

Open AccessFeature PaperArticle

Enhanced Treatment of Basic Red 46 by Ozonation in a Rotating Packed Bed with Liquid Detention

by Peng Xu, Tianyang Wu, Yang Xiang, Jimmy Yun and Lei Shao

Processes 2023, 11(5), 1345; https://doi.org/10.3390/pr11051345 - 26 Apr 2023

Viewed by 910

Abstract

This study investigated the use of ozone in a rotating packed bed (RPB) with liquid detention for the treatment of Basic Red 46 (BR-46). Liquid detention means that liquid accumulates at the lower section to a certain level in the RPB, which leads [...] Read more.

This study investigated the use of ozone in a rotating packed bed (RPB) with liquid detention for the treatment of Basic Red 46 (BR-46). Liquid detention means that liquid accumulates at the lower section to a certain level in the RPB, which leads to longer liquid residence time and greater liquid holdup in the packing and cavity in the RPB. The experimental results showed that the presence of liquid detention in the RPB significantly enhanced the BR-46 treatment effect and ozone absorption rate. With 200 mL of liquid detention in the RPB, the decolorization rate, COD degradation rate, and ozone absorption rate were 34.7%, 62.8%, and 80.0% higher than those without liquid detention. The effects of the rotational speed of the RPB, ozone concentration, initial BR-46 concentration, liquid and gas flow rates on BR-46 degradation were also investigated, and it was found that the high-gravity environment is beneficial to the degradation of BR-46. These results suggest that with the utilization of the liquid detention phenomena in the high-gravity devices, the applications of the high-gravity technology can be extended to the processes where a long liquid residence time is required. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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16 pages, 2580 KiB

Open AccessArticle

Comparative Analysis of Three WEEE Management Scenarios Based on LCA Methodology: Case Study in the Municipality of Iasi, Romania

by Simona Cecilia Ghiga, Isabela Maria Simion, Cătălina Filote, Mihaela Roșca, Raluca Maria Hlihor and Maria Gavrilescu

Processes 2023, 11(5), 1305; https://doi.org/10.3390/pr11051305 - 23 Apr 2023

Cited by 4 | Viewed by 1490

Abstract

The increasing consumption of electrical and electronic equipment (EEE), correlated with the fast innovation pace in this field, generates a large amount of annual waste. The current established management practices cannot keep up with it, and the results are of increased significance given [...] Read more.

The increasing consumption of electrical and electronic equipment (EEE), correlated with the fast innovation pace in this field, generates a large amount of annual waste. The current established management practices cannot keep up with it, and the results are of increased significance given the negative effects on the environment and human health. Thus, the current study aimed to analyze the environmental impact of three different scenarios of waste electrical and electronic equipment (WEEE) management, following population awareness campaigns regarding its collection in the Municipality of Iasi, Romania. Data processing was carried out considering Life Cycle Assessment (LCA) methodology with the established functional unit for each scenario according to the collected amount. The results were quantified using the CML2001 and ReCiPe methods and showed that the highest environmental impact was obtained for scenario II (S2) (1.59 × 10⁻⁷ pers. equiv. using the CML2001 method and 32.7 pers. equiv. using the ReCiPe method), while the lowest for scenario I (S1) (6.42 × 10⁻⁸ pers. equiv. using the CML2001 method and 13.8 pers. equiv. using the ReCiPe method). The process with the highest contribution to the total environmental impact was the collection stage for all scenarios, with the exception of scenario S2, in which case the highest value was generated for the landfill process following the application of the ReCiPe method (39.93%). The current study provides value to a critical issue in the environmental area and supports the development of sustainable WEEE management processes. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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12 pages, 3545 KiB

Open AccessFeature PaperArticle

Prediction of Oxygen Content in Boiler Flue Gas Based on a Convolutional Neural Network

by Zhenhua Li, Guanghong Li and Bin Shi

Processes 2023, 11(4), 990; https://doi.org/10.3390/pr11040990 - 24 Mar 2023

Cited by 2 | Viewed by 1348

Abstract

As one of the core pieces of equipment of the thermal power generation system, the economic and environmental performance of a boiler determines the energy efficiency of the thermal power generation unit. The oxygen content in boiler flue gas is an important parameter [...] Read more.

As one of the core pieces of equipment of the thermal power generation system, the economic and environmental performance of a boiler determines the energy efficiency of the thermal power generation unit. The oxygen content in boiler flue gas is an important parameter reflecting the combustion status of the furnace, and accurate prediction of flue gas oxygen content is of great significance for online boiler optimization. In order to solve the online prediction problem of the oxygen content in boiler flue gas, a CNN is applied to build a time series prediction model, which takes the time series samples within a fixed time window as the input of the model and uses several feature extraction modules containing convolutional, activation, and pooling layers for feature extraction and compression, and the model output is the oxygen content in boiler flue gas. Since the oxygen content in boiler flue gas is not only correlated with other variables but also influenced by its own historical trend, the input of the CNN model is improved, and an oxygen content in boiler flue gas time series prediction model (TS-CNN) is established, which takes the historical values of the boiler flue gas oxygen content as the input of the model. The comparison test results show that the

R^{2}

and

R M S E

of the TS-CNN model are 0.8929 and 0.1684, respectively. The prediction accuracy is higher than the CNN model, LSSVM model, and BPNN model by 18.6%, 31.2%, and 54.6%, respectively. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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19 pages, 4418 KiB

Open AccessArticle

Management of Agricultural Water Containing Acetimidothioic Acid Pesticide through Catalytic Oxidation to Facilitate Reclaimed Water Recycling for Sustainable Food Production

by Ehssan Ahmed Hassan, Maha A. Tony, Hossam A. Nabwey and Mohamed M. Awad

Processes 2023, 11(3), 792; https://doi.org/10.3390/pr11030792 - 07 Mar 2023

Viewed by 1078

Abstract

Agro-industrial discharge contains acetimidothioic acid, which is commercially named “Lanox 90” and is a widely applied insecticide in greenhouses, and the result is wastewater loaded with this insecticide. Treating such wastewater is a must to reduce the environmental impact as well as to [...] Read more.

Agro-industrial discharge contains acetimidothioic acid, which is commercially named “Lanox 90” and is a widely applied insecticide in greenhouses, and the result is wastewater loaded with this insecticide. Treating such wastewater is a must to reduce the environmental impact as well as to facilitate the opportunity for water recycling. Thus, the present work introduced Montmorillonite (MMT) clay as a novel Fenton reaction source to treat wastewater loaded with Lanox 90 insecticide as a benign sustainable strategy. Scanning electron microscopy (SEM) supported with energy-dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the MMT sample. Response surface methodology based on Box–Behnken analysis was selected to optimize the parametric circumstances. The optimized parameters of the proposed technique were obtained at a pH of 2.6 with the addition of 0.8 and 854 mg/L of MMT and H₂O₂, respectively, to attain the highest predicted Lanox 90 removal rate of 97%. Analysis of variance (ANOVA) was used to examine the statistical data and displayed a significant quadratic model. Ultimately, the results reveal that the oxidation system is exothermic and has a non-spontaneous nature, and the reaction kinetics are categorized according to the second-order reaction kinetic rate. The results of the current study indicate the importance of MMT for treating wastewater. These results confirm the possibility of using oxidation technique as a suitable candidate for greenhouse effluent management to enhance the efficiency of water recycling for smart irrigation. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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13 pages, 3071 KiB

Open AccessArticle

Estimation of ¹³⁷Cs Distribution and Recovery Using Various Types of Sorbents in the Black Sea Surface Layer

by Nikolay A. Bezhin, Dmitriy A. Kremenchutskii, Evgeniy V. Slizchenko, Ol’ga N. Kozlovskaia, Iuliia G. Shibetskaia, Vitaliy V. Milyutin and Ivan G. Tananaev

Processes 2023, 11(2), 603; https://doi.org/10.3390/pr11020603 - 16 Feb 2023

Cited by 2 | Viewed by 1231

Abstract

Monitoring ¹³⁷Cs in seawater is necessary for the timely detection of radioactive contamination. The possibility of sorption and the sorption efficiency of ¹³⁷Cs from seawater were studied for the first time during several cruises of the R/V (research vessel) Professor Vodyanitsky [...] Read more.

Monitoring ¹³⁷Cs in seawater is necessary for the timely detection of radioactive contamination. The possibility of sorption and the sorption efficiency of ¹³⁷Cs from seawater were studied for the first time during several cruises of the R/V (research vessel) Professor Vodyanitsky using various types of sorbents based on transition metal ferrocyanides (Anfezh, Niket, Uniket, FSS, FD-M, FIC, Termoxid 35, NKF-C) and zirconium phosphate (Termoxid 3A). The influence of the seawater flow rate and volume of the sorbent used for the recovery of ¹³⁷Cs was estimated. The ferrocyanide sorbents Niket, Uniket, Termoxid 35, and FIC showed the best sorption efficiency (60–100%) at a seawater flow rate of 2–4 column volumes per minute. The data obtained during three cruises on the R/V Professor Vodyanitsky were analyzed. A detailed (28 sampling points) spatial distribution of ¹³⁷Cs in the Black Sea along the southern coast of Crimea was studied using the sorbents that showed the best characteristics. An increase in ¹³⁷Cs activity in the study area was not found, and the average activity was 9.01 ± 0.87 Bq/m³. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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13 pages, 3596 KiB

Open AccessFeature PaperArticle

Thermal Stability for the Continuous Production of γ-Valerolactone from the Hydrogenation of N-Butyl Levulinate in a CSTR

by Wenel Naudy Vásquez Salcedo, Bruno Renou and Sébastien Leveneur

Processes 2023, 11(1), 237; https://doi.org/10.3390/pr11010237 - 11 Jan 2023

Cited by 2 | Viewed by 1365

Abstract

γ-valerolactone can be a game-changer in the chemical industry because it could substitute fossil feedstocks in different fields. Its production is from the hydrogenation of levulinic acid or alkyl levulinates and can present some risk of thermal runaway. To the best of our [...] Read more.

γ-valerolactone can be a game-changer in the chemical industry because it could substitute fossil feedstocks in different fields. Its production is from the hydrogenation of levulinic acid or alkyl levulinates and can present some risk of thermal runaway. To the best of our knowledge, no studies evaluate the thermal stability of this production in a continuous reactor. We simulated the thermal behavior of the hydrogenation of butyl levulinate over Ru/C in a continuous stirred-tank reactor and performed a sensitivity analysis. The kinetic and thermodynamic constants from Wang et al.’s articles were used. We found that the risk of thermal stability is low for this chemical system. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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15 pages, 3169 KiB

Open AccessArticle

Experimental Investigation on Pyrolysis of Domestic Plastic Wastes for Fuel Grade Hydrocarbons

by Praveen Kumar Ghodke, Amit Kumar Sharma, Krishna Moorthy, Wei-Hsin Chen, Alok Patel and Leonidas Matsakas

Processes 2023, 11(1), 71; https://doi.org/10.3390/pr11010071 - 28 Dec 2022

Cited by 10 | Viewed by 3069

Abstract

Plastics usage is rising daily because of increased population, modernization, and industrialization, which produces a lot of plastic garbage. Due to their various chemical structures, long chain polymeric compositions, and thermal/decomposition behavior, it is challenging to recycle these plastic wastes into hydrocarbon fuels. [...] Read more.

Plastics usage is rising daily because of increased population, modernization, and industrialization, which produces a lot of plastic garbage. Due to their various chemical structures, long chain polymeric compositions, and thermal/decomposition behavior, it is challenging to recycle these plastic wastes into hydrocarbon fuels. In the current work, domestic plastic waste was pyrolyzed at 473 to 973 K in a fixed bed reactor and compared with the three virgin plastics LDPE (low-density polyethylene), HDPE (high-density polyethylene), and PP (polypropylene), as well as a mixture of the three (virgin mixed plastics). The pyrolysis results showed that maximum liquid hydrocarbons obtained from HDPE, LDPE, PP, mixed plastic, and domestic waste were 64.6 wt.%, 62.2 wt.%, 63.1 wt.%, 68.6 wt.%, and 64.6 wt.% at 773 K, respectively. The composition of liquid fuels was characterized using FTIR and GC-MS, which showed a wide spectrum of hydrocarbons in the C8–C20 range. Furthermore, liquid fuel characteristics such as density, viscosity, fire and flash point, pour point, and calorific value were examined using ASTM standards, and the results were found to be satisfactory. This study provides an innovative method for recycling waste plastics into economical hydrocarbon fuel for use in transportation. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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16 pages, 6960 KiB

Open AccessArticle

Research on the Application of Coal Gasification Slag in Soil Improvement

by Ruimei Zhang, Xiaonan Li, Kai Zhang, Pengfei Wang, Peifeng Xue and Hailong Zhang

Processes 2022, 10(12), 2690; https://doi.org/10.3390/pr10122690 - 13 Dec 2022

Cited by 3 | Viewed by 1264

Abstract

SEM, particle size analysis, and contaminant content of coarse coal gasification slag (CCGS) produced by Shenhua Xinjiang Chemical Co., Ltd. were measured, respectively, and the physicochemical properties of the soil after improvement using gasification slag were investigated in this paper. The results showed [...] Read more.

SEM, particle size analysis, and contaminant content of coarse coal gasification slag (CCGS) produced by Shenhua Xinjiang Chemical Co., Ltd. were measured, respectively, and the physicochemical properties of the soil after improvement using gasification slag were investigated in this paper. The results showed that the slag was porous, the particle size was small and the pollutant content was extremely low. Its pollutants were closely related to the pollutants in the raw coal. The coarse slag had a limited effect on soil particle size and texture improvement; the soil water retention performance increased with the increase of proportion of the slag, while pH and conductivity decreased; the improvement effect on soil SOM and available potassium was remarkable; the larger the proportion of the slag, the stronger the effect on maintaining soil alkali-hydrolyzed nitrogen, ammonium nitrogen, and available phosphorus. However, the effect was small, and increased the ion content, especially the cation in soil, and the sum of the eight soil ions before and after evaporation decreased. The results demonstrated that the CCGS generated by the corporation is feasible for soil improvement, and the study has important reference value for the comprehensive utilization of coal gasification slag. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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Review

Jump to: Editorial, Research, Other

21 pages, 26595 KiB

Open AccessReview

Bibliometric Analysis of Constructed Wetlands with Ornamental Flowering Plants: The Importance of Green Technology

by José Luis Marín-Muñiz, Irma Zitácuaro-Contreras, Gonzalo Ortega-Pineda, Luis Manuel Álvarez-Hernández, Karina Elizabeth Martínez-Aguilar, Aarón López-Roldán and Sergio Zamora

Processes 2023, 11(4), 1253; https://doi.org/10.3390/pr11041253 - 19 Apr 2023

Cited by 3 | Viewed by 1605

Abstract

The use of constructed wetlands (CWs) for wastewater treatment has earned high interest around the world. However, innovations to improve its removal efficiency and adoption have been suggested in the last decades. For instance, the use of ornamental flowering plants (OFP), which make [...] Read more.

The use of constructed wetlands (CWs) for wastewater treatment has earned high interest around the world. However, innovations to improve its removal efficiency and adoption have been suggested in the last decades. For instance, the use of ornamental flowering plants (OFP), which make wetland treatment systems more aesthetic and is an option for the production of commercial flowers while the water is cleansed. The objectives of this study were to identify through a bibliometric analysis (2000–2022) the main OFP that have been used in CWs and their functionality as phytoremediators (removal effects), as well as the authors, collaborations, main investigations, and the countries where such investigations have been carried out. To this respect, 10,254 studies on CWs were identified. The United States and China were the leading countries in the use of this eco-technology. Subsequently, regarding the use of OFP, the analysis revealed 92 studies on this matter in which Mexico has three researchers who lead the use of OFP in CWs (almost 40% of publications of CWs with OFP), where the main species studied include Canna hybrids, Zantedeschia aethiopica, Strelitzia reginae, Iris species, Spathiphyllum sp., and Anturium sp. These species may remove between 30–90% of pollutants of organic compounds, 30–70% of heavy metals and drugs, and about 99.9% of pathogens. Thus, this study may help researchers to identify OFP for new CWs design, and to know new future research directionsand collaboration approaches in this area using multipurpose alternatives like those of CWs with OFP. More research can still be carried out on the use of CWs with OFP in temperate climates, as well as evaluating the influence of different substrates and water flow on the growth of these plants. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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Other

Jump to: Editorial, Research, Review

14 pages, 976 KiB

Open AccessPerspective

Mini-Review of Best Practices for Greenhouse Gas Reduction in Singapore’s Semiconductor Industry

by Shikai Zhu, Haoqian Hu, Haoyi Yang, Yunzhuo Qu and Yuanzhe Li

Processes 2023, 11(7), 2120; https://doi.org/10.3390/pr11072120 - 16 Jul 2023

Cited by 6 | Viewed by 1893

Abstract

Climate change is an urgent global concern driven by human activities and the subsequent rise in greenhouse gas (GHG) emissions. The semiconductor industry has emerged as a significant contributor to GHG emissions, yet there is a lack of clear guidelines for effective reduction [...] Read more.

Climate change is an urgent global concern driven by human activities and the subsequent rise in greenhouse gas (GHG) emissions. The semiconductor industry has emerged as a significant contributor to GHG emissions, yet there is a lack of clear guidelines for effective reduction methods specifically tailored to domestic and international semiconductor manufacturing. This mini-review addresses this gap by proposing implementation principles for optimal control technology aimed at mitigating GHG emissions in the semiconductor industry. Drawing upon guidance from the Intergovernmental Panel on Climate Change (IPCC) and established reduction methods, our focus is on the deployment of efficient exhaust gas destruction equipment for removing GHGs from critical processes such as Etching, ThinFilm (including chemical/physical vapor deposition), and Diffusion. By examining and consolidating current best practices, this review provides a foundation for developing comprehensive guidelines and standards that support the semiconductor industry’s transition to more sustainable operations. Considering the vast body of literature in this field, we highlight the significance of this study as it contributes to the ongoing research efforts in reducing GHG emissions. The objective of this study is to identify research gaps and motivate further investigations, while also providing practical recommendations for reducing GHG emissions in the semiconductor industry. Full article

(This article belongs to the Special Issue 10th Anniversary of Processes: Recent Advances in Environmental and Green Processes)

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