Resources

14 pages, 4073 KiB

Open AccessArticle

Co-Hydrothermal Carbonization of Grass and Olive Stone as a Means to Lower Water Input to HTC

by Rocío García-Morato, Silvia Román, Beatriz Ledesma and Charles Coronella

Resources 2023, 12(7), 85; https://doi.org/10.3390/resources12070085 - 21 Jul 2023

Cited by 1 | Viewed by 1087

One drawback of biomass hydrothermal treatment (HTC) is the need of a water supply, which is especially important in the case of lignocellulosic biomass. This study has investigated the synergy resulting from co-HTC of two residual biomass materials that significantly differ in their [...] Read more.

One drawback of biomass hydrothermal treatment (HTC) is the need of a water supply, which is especially important in the case of lignocellulosic biomass. This study has investigated the synergy resulting from co-HTC of two residual biomass materials that significantly differ in their physico-chemical compositions: (a) olive stone, OS, a hard and high-quality biomass, with low N content, whose potential to give a high heating value briquette by HTC has been proven, and (b) fresh grass pruning, GP, as it is gathered from gardens, with a high water content, moderate N fraction, and low calorific value. The work specifically focuses on the water saving that can be attained when the liquid product produced by one of them (grass, with 80% of moisture) can supply part of the water needed by the other (olive stone) when both are subjected to HTC simultaneously. It was found that, when instead of water, an additional amount of fresh GP is added (in particular 40 out of 110 g of water was provided by 54 g of GP), and a more basic processing water is obtained (pH of co-HTC increased by 40%, in relation of single OS processes). This in turn did not have a remarkable effect on OS final SY at any of the two temperatures studied (200 and 220 °C), not on the C densification. Other features such as N content of resulting OS hydrochars showed a rise in the case of hybrid processes, from 0.2% to 3.3%. Other features that were affected on OS HTC products because of the presence of the GP in co-HTC were the HC surface structure, hydrophobicity, and the presence of surface functionalities and their thermal stability towards pyrolysis; processing water also showed changes on mineral content when both biomasses there blended. Proving that a biomass like OS can be hydrothermally treated by a hybrid process involving less water, without being detrimental in terms of final SY and energy densification, can open a field of research aimed to make HTC processes more efficient in terms of hydric balance. Full article

(This article belongs to the Special Issue Energy and Nutrient Recovery by Hydrothermal Treatments)

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20 pages, 8073 KiB

Open AccessArticle

Fluoride Removal from Aqueous Medium Using Biochar Produced from Coffee Ground

by Hellem Victoria Ribeiro dos Santos, Paulo Sérgio Scalize, Francisco Javier Cuba Teran and Renata Medici Frayne Cuba

Resources 2023, 12(7), 84; https://doi.org/10.3390/resources12070084 - 17 Jul 2023

Cited by 1 | Viewed by 1595

Abstract

Low concentrations of fluoride (F⁻) in drinking water are beneficial for oral health, but the natural occurrence of high F⁻ content has been reported in various groundwater sources, posing a continuous ingestion threat to humans. The utilization of biochar (BC) [...] Read more.

Low concentrations of fluoride (F⁻) in drinking water are beneficial for oral health, but the natural occurrence of high F⁻ content has been reported in various groundwater sources, posing a continuous ingestion threat to humans. The utilization of biochar (BC) produced from residual biomass has emerged as a technically, economically, and environmentally sustainable alternative for fluoride removal through adsorption. Therefore, this study aimed to investigate the physicochemical characteristics of BC derived from coffee grounds and the influence of various factors on the adsorption process of F⁻ in aqueous media, including pH, adsorbent dosage, contact time, temperature, and initial F⁻ concentration. The BC exhibited a surface area of 12.94 m²·g⁻¹ and a pore volume of 0.0349 cm³·g⁻¹. The adsorption process was strongly pH dependent, demonstrating a significant decline in performance as pH increased from 2.0 onwards. The majority of F⁻ removal occurred within the first 5 min, reaching adsorption equilibrium after 1 h of testing, regardless of the initial F⁻ concentration employed. The data fitting to the Webber–Morris model indicated a two-step adsorption process on BC, with the first step being external surface sorption and the second step being intra-articular diffusion. The process was determined to be endergonic, and the data satisfactorily matched both the Freundlich and Langmuir models, with a q_m of 0.53 mg·L⁻¹ (T = 55 °C), indicating the predominance of physisorption. The findings suggest the potential of coffee grounds for BC production; nevertheless, surface structure modifications are necessary to enhance F⁻ affinity and subsequently improve adsorption capacity. Full article

(This article belongs to the Special Issue Energy and Nutrient Recovery by Hydrothermal Treatments)

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10 pages, 1093 KiB

Open AccessArticle

Comparative Study of the Yield and Chemical Profile of Rose Oils and Hydrosols Obtained by Industrial Plantations of Oil-Bearing Roses in Bulgaria

by Ana Dobreva, Deyana Nedeva and Milka Mileva

Resources 2023, 12(7), 83; https://doi.org/10.3390/resources12070083 - 10 Jul 2023

Cited by 1 | Viewed by 2983

Abstract

Bulgaria is famous for its oil-bearing rose. R. damascena Mill. and R. alba L. are mainly cultivated in the country, but a recent survey of industrial plantations in 2020 revealed that R. centifolia L. and hybrids of R. damascena Mill. X R. gallica [...] Read more.

Bulgaria is famous for its oil-bearing rose. R. damascena Mill. and R. alba L. are mainly cultivated in the country, but a recent survey of industrial plantations in 2020 revealed that R. centifolia L. and hybrids of R. damascena Mill. X R. gallica L. are also common in the rose valley. Although their essential oil cannot be compared in quality with the classic, these species are preferred by farmers with high yields of flowers and resistance to diseases and pests. All these roses are also used to produce rose water and extracts. The aim of this investigation was to compare the yield and chromatographic fingerprints of seven rose oils and hydrosols produced in Bulgaria. The quantitative composition of the main components of the oils was compared with the norms of the world standards. Our study showed that the yield of essential oil from these roses was in the range of 0.015–0.048%. The main group in the chemical composition is terpene alcohols, which vary in range: geraniol (15.85–34.02%), citronellol (6.70–28.72%), and nerol (5.80–11.90%) but with a different ratio. Hydrocarbons are represented by saturated aliphatic homologs with an odd number of carbon atoms, the main ones being nonadecane (8.10–22.67%), heneicosane (4.37–10.21%), heptadecane (1.07–2.98%), and triclosan (0.81–5.90%). In contrast, the chemical profile of the hydrosols was performed using phenylethyl alcohol (27.45–69.88%), geraniol (13.72–28.67%), and citronelol+nerol (4.56–17.37%). The results show that the presence of plantations with a genotype different from that of R. damascena implies differences in the quality of rose oils and hydrosols. This determines their properties of use. Full article

(This article belongs to the Special Issue Resource Extraction from Agricultural Products/Waste)

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17 pages, 7462 KiB

Open AccessArticle

New Bioretention Drainage Channel as One of the Low-Impact Development Solutions: A Case Study from Poland

by Agnieszka Stec and Daniel Słyś

Resources 2023, 12(7), 82; https://doi.org/10.3390/resources12070082 - 10 Jul 2023

Cited by 5 | Viewed by 1351

Abstract

In recent years, as a result of intensive urbanisation, a significant increase in the surface of impermeable areas has been observed, which results in changes in the hydrological cycle of catchments. In order to counteract these changes, low-impact development (LID) solutions are increasingly [...] Read more.

In recent years, as a result of intensive urbanisation, a significant increase in the surface of impermeable areas has been observed, which results in changes in the hydrological cycle of catchments. In order to counteract these changes, low-impact development (LID) solutions are increasingly being implemented in urban catchments, including bioretention systems. Taking this into account, a new bioretention drainage channel (BRC) was designed, whose main task is retention, infiltration, and pre-treatment of rainwater. The pilot laboratory tests carried out on two BRC prototypes (K1 and K2) showed that the average rate of reduction of mineral-suspended solids from rainwater was 69% and 57%, respectively, for K1 and K2. Analysing the results of the research, it was found that the bioretention drainage channel is characterised by very high efficiency in removing petroleum hydrocarbons from rainwater, and the reduction rate of these pollutants for both the K1 and K2 channels was close to 100%. In turn, hydrodynamic studies carried out on the model of the urban catchment showed that the implementation of BRCs will reduce the peak runoff by more than 82%, and the maximum flow in the sewage network by 83%. Full article

(This article belongs to the Special Issue Alternative Water and Energy Systems in the Buildings)

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19 pages, 4576 KiB

Open AccessArticle

Improvement of MBBR Performance by the Addition of 3D-Printed Biocarriers Fabricated with 13X and Bentonite

by Dimitra C. Banti, Petros Samaras, Afroditi G. Chioti, Anastasios Mitsopoulos, Michail Tsangas, Antonis Zorpas and Themistoklis Sfetsas

Resources 2023, 12(7), 81; https://doi.org/10.3390/resources12070081 - 10 Jul 2023

Viewed by 1312

Abstract

The current study investigated the performance of a moving bed biofilm reactor (MBBR), when adding 3D-printed biocarriers fabricated with 13X and bentonite (MBBR 3D), when using K1 commercial biocarriers (MBBR K1) and when not adding biocarriers at all (control MBBR). For the evaluation [...] Read more.

The current study investigated the performance of a moving bed biofilm reactor (MBBR), when adding 3D-printed biocarriers fabricated with 13X and bentonite (MBBR 3D), when using K1 commercial biocarriers (MBBR K1) and when not adding biocarriers at all (control MBBR). For the evaluation of the MBBR efficiency, various physicochemical parameters were measured, while biofilm extracted from the biocarriers was evaluated. The findings suggest that there is an optimal biodegradation of the organic load in all MBBR units. The nitrification and denitrification processes were improved in MBBR 3D as compared to the control MBBR and MBBR K1. The dry mass of the biofilm in the 3D-printed biocarriers was two orders of magnitude larger than in the K1 biocarriers. Moreover, in the K1 biocarriers the mass of the biofilm varied in relation to time, since it could not be protected inside the holes, something that did not happen with the 3D-printed biocarriers. Finally, it was found, mostly in MBBR 3D and less in MBBR K1, that the growth of nitrifying bacteria and heterotrophs inside the units increased the biomass production in the form of soluble microbial products, which in turn favored the adhesion of biomass on the surface of biocarriers. Full article

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20 pages, 1768 KiB

Open AccessArticle

Study of the Relationship between Economic Growth and Greenhouse Gas Emissions of the Shanghai Cooperation Organization Countries on the Basis of the Environmental Kuznets Curve

by Amina Andreichyk and Pavel Tsvetkov

Resources 2023, 12(7), 80; https://doi.org/10.3390/resources12070080 - 06 Jul 2023

Cited by 12 | Viewed by 2279

Abstract

The present study contributes to the ongoing debate on environmental sustainability and the low-carbon agenda in terms of an analysis of a relatively new international association, the Shanghai Cooperation Organization (SCO). Based on panel data from SCO countries from 2000 to 2020, the [...] Read more.

The present study contributes to the ongoing debate on environmental sustainability and the low-carbon agenda in terms of an analysis of a relatively new international association, the Shanghai Cooperation Organization (SCO). Based on panel data from SCO countries from 2000 to 2020, the hypothesis of the existence of the Environmental Kuznets Curve (EKC) was tested. The results showed the validity of the EKC hypothesis for the SCO countries; in particular, the gross domestic product and natural resource rents have a connection with greenhouse gas (GHG) emissions, while trade openness, foreign direct investment and the use of renewable energy sources reduce GHG emissions in the long term. It was also found that the effect of economic growth on GHG emissions in the long term in the SCO countries has the form of an inverse N-curve. Based on the analysis performed, recommendations are offered to improve energy policy in the field of alternative energy sources, natural resources—rents on them, openness to foreign markets and attracting foreign investment. Full article

(This article belongs to the Special Issue Resource Provision of the Sustainable Development under Global Shocks: 2022 Viewpoint)

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17 pages, 12056 KiB

Open AccessArticle

Investigation of the Usability of Reduced Alkalinity Red Mud in the Building Material Industry

by Miklós Jakab, Gergely Balázs Patthy, Tamás Korim and Éva Makó

Resources 2023, 12(7), 79; https://doi.org/10.3390/resources12070079 - 03 Jul 2023

Viewed by 1100

Abstract

Untreated and pH-reduced red mud is used as a potential raw material in ceramic technology. During the alkalinity reduction process, CO₂ is bubbled through the untreated red mud, which is particularly important as it can reduce the CO₂ content of the [...] Read more.

Untreated and pH-reduced red mud is used as a potential raw material in ceramic technology. During the alkalinity reduction process, CO₂ is bubbled through the untreated red mud, which is particularly important as it can reduce the CO₂ content of the atmosphere, and the pH of the red mud. Therefore, this method serves as a CO₂ capture technique that utilizes waste as a raw material with low costs. Besides, reducing CO₂ emission, it allows the production of material suitable for brick manufacturing from waste. In this study, treated and reduced alkalinity red mud was mixed with clay in the range of 5–30 wt%, and the physical, chemical, mechanical, and technologically important properties of the dried and sintered bricks were examined. The application of reduced alkalinity red mud as an additive offers advantages, as the resulting bricks require less water for processing, are less sensitive to drying, and their strength values exceed those of the commercially available bricks. Therefore, the technique presented in the study enables the production of bricks and roof tiles with advantageous properties using waste materials. Full article

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26 pages, 3729 KiB

Open AccessArticle

Inter-Sectoral Economic Linkages in the Mining Industries of Botswana and Tanzania: Analysis Using Partial Hypothetical Extraction Method

by Fitsum Semere Weldegiorgis, Evelyn Dietsche and Shabbir Ahmad

Resources 2023, 12(7), 78; https://doi.org/10.3390/resources12070078 - 29 Jun 2023

Cited by 2 | Viewed by 2641

Abstract

Fiscal and local content policies aimed at promoting linkages between mining and other economic sectors have been informed by theories built on historical observations dating back to the 1950s. This paper contends that there is a need to rethink theories about mining-based economic [...] Read more.

Fiscal and local content policies aimed at promoting linkages between mining and other economic sectors have been informed by theories built on historical observations dating back to the 1950s. This paper contends that there is a need to rethink theories about mining-based economic linkages and the prospects for structural change based on an improved understanding of existing and potential inter-sectoral linkages. Using the input–output tables for Tanzania and Botswana, we apply the Partial Hypothetical Extraction Method within the Leontief and Gosh input–output frameworks to examine the linkages between the mining and quarrying sector and other economic sectors within these two economies. We find that, for Botswana, possible linkage pathways lie in scaling-up coal, soda ash and salt mining and investing in glass, polymer, and chemicals manufacturing. For Tanzania, opportunities for linkage pathways lie with the mining and manufacturing of non-metallic and construction materials as well as metallic minerals and natural gas. For both countries, the prospects for transforming their economies away from a heavy reliance on mineral extraction hinges on leveraging extractives for infrastructure, innovative technology, and technical skills, as well as capturing business opportunities, knowledge, and financial returns to invest in more diversified economic activities. Full article

(This article belongs to the Special Issue Recent Trends in Resources considering Sustainability, Economy, and Corporate Social Responsibility)

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22 pages, 2472 KiB

Open AccessFeature PaperArticle

The Recovery of Bioactive Compounds from Olive Pomace Using Green Extraction Processes

by Marina Stramarkou, Theodora-Venetia Missirli, Konstantina Kyriakopoulou, Sofia Papadaki, Athanasios Angelis-Dimakis and Magdalini Krokida

Resources 2023, 12(7), 77; https://doi.org/10.3390/resources12070077 - 29 Jun 2023

Cited by 4 | Viewed by 1494

Abstract

In this study, solid olive mill waste (SOMW) was used to obtain antioxidant compounds using solid–liquid extraction. The effect of different extraction methods, namely microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), Soxhlet, and conventional solvent extraction, on the yield, total phenolics, and total antioxidant [...] Read more.

In this study, solid olive mill waste (SOMW) was used to obtain antioxidant compounds using solid–liquid extraction. The effect of different extraction methods, namely microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), Soxhlet, and conventional solvent extraction, on the yield, total phenolics, and total antioxidant activity of SOMW extracts was investigated. Untreated and dried SOMW were subjected to extraction with water and methanol. The antioxidant activity of the extracts was evaluated using the DPPH assay, while their total phenolic content was measured using the Folin–Ciocalteu method. For the characterisation of the extracts, HPLC-DAD analysis was performed. The results showed that the extraction yield was significantly influenced (p < 0.05) by the solvent used, the material treatment prior to extraction, the moisture content of SOMW samples, and the extraction time. The optimised parameters were water, as the extraction solvent, and MAE as the extraction technique (extraction temperature of 50 °C and time of 1 h). The evaluation of the antioxidant activity of the extracts indicated that phenolics were the dominant bioactive compounds. The extracts were found to be rich in several hydroxytyrosol derivatives. Therefore, SOMW can be a valuable resource for bioactive compounds using conventional and innovative extraction techniques. Full article

(This article belongs to the Special Issue Resource Extraction from Agricultural Products/Waste)

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16 pages, 2399 KiB

Open AccessArticle

Sustainable Municipal Waste Management during the COVID-19 Pandemic—A Case Study of Poland

by Weronika Urbańska, Anna Janda, Magdalena Osial and Mateusz Słowikowski

Resources 2023, 12(7), 76; https://doi.org/10.3390/resources12070076 - 29 Jun 2023

Cited by 2 | Viewed by 1510

Abstract

With the outbreak of the COVID-19 pandemic, the waste management sector had to face new challenges, e.g., changes in the size and composition of the waste stream, or the presence of potentially infectious waste. This article is based on a case study in [...] Read more.

With the outbreak of the COVID-19 pandemic, the waste management sector had to face new challenges, e.g., changes in the size and composition of the waste stream, or the presence of potentially infectious waste. This article is based on a case study in Poland. The data analysis showed that the increase in municipal waste mass during the pandemic did not differ from statistics observed in previous years and ranged from 0.3 to 0.5 million tons per year. Lifestyle changes caused a decrease in the amount of waste generated outside households. Social migrations contributed to rapid changes in the mass of waste generated in selected agglomerations by up to 80 kg/capita. In the waste stream, significant amounts of specific groups of waste related to the pandemic (“corona waste”) as well as packaging and food waste were noted. Despite the pandemic, in 2020, Poland recorded an increase in selective waste collection by 6.7 percentage points (pp.) Data on municipal waste management showed an increase in the mass of waste sent for recycling by 0.7 million tons, while the mass of landfilled waste decreased by 0.3 million tons. The observed positive changes in waste management allow the implementation of sustainable development assumptions to a greater extent. Full article

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13 pages, 2317 KiB

Open AccessArticle

Global Warming Potential and Waste Handling of Pearl Farming in Ago Bay, Mie Prefecture, Japan

by Dheanara Pinka and Kazuyo Matsubae

Resources 2023, 12(7), 75; https://doi.org/10.3390/resources12070075 - 27 Jun 2023

Viewed by 2379

Abstract

Pearl farming (PF) represents a significant portion of the world’s total aquaculture production and is a growing multibillion-dollar sector of mollusk aquaculture. However, PF in Mie Prefecture, Japan, has resulted in the deterioration of environmental conditions in Ago Bay, and its environmental impacts [...] Read more.

Pearl farming (PF) represents a significant portion of the world’s total aquaculture production and is a growing multibillion-dollar sector of mollusk aquaculture. However, PF in Mie Prefecture, Japan, has resulted in the deterioration of environmental conditions in Ago Bay, and its environmental impacts are yet to be evaluated using a life-cycle assessment (LCA). Thus, in this study, a cradle-to-gate LCA using 1 kg of pearl produced in Ago Bay was conducted. The key results showed that the global warming potential (GWP) was equivalent to 4.98 kg CO₂, which is lower than the GWPs of metals, such as gold and silver, commonly used in jewelry production. Meanwhile, the waste handling of PF is progressing, with current efforts being focused on extracting calcium carbonate, exporting shell waste, and reducing plastic waste. These findings provide critical insights for achieving sustainable pearl production aquaculture. Full article

(This article belongs to the Special Issue Women's Special Issue Series: Sustainable Resource Management)

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21 pages, 25326 KiB

Open AccessArticle

The Geo-Cultural Heritage of Kos Revisited: Web-GIS Applications and Storytelling Promoting the Well-Known Island of Dodecanese, Greece

by Varvara Antoniou, Dimitris Panousis, Elisavet Nikoli, Anna Katsigera, Othonas Vlasopoulos and Paraskevi Nomikou

Resources 2023, 12(7), 74; https://doi.org/10.3390/resources12070074 - 25 Jun 2023

Cited by 1 | Viewed by 2009

Abstract

Kos is the third largest island of the Dodecanese, located in the southeastern Aegean Sea, Greece. The island’s remarkable location both in a prominent geodynamic space and at a crossroads of East, West and South has endowed it with a unique wealth of [...] Read more.

Kos is the third largest island of the Dodecanese, located in the southeastern Aegean Sea, Greece. The island’s remarkable location both in a prominent geodynamic space and at a crossroads of East, West and South has endowed it with a unique wealth of geological, biological, cultural, and traditional heritage. Steep mountain ranges consisting of Alpine Mesozoic rocks alternate with low-altitude plateaus featuring marine and lacustrine sediments that contain fossils of past life. In addition, the transition of barren land to lush forests where numerous species of flora and fauna thrive is unique to Greek ecosystems. This environment hosted civilizations and activities that gradually led to the present-day cultural and religious state of the island, where people and nature coexist respectfully on one of the country’s most favourite destinations. In an effort to further enhance the public’s awareness of the geo-cultural heritage of Kos, an online ESRI Hub was created, featuring several individual ESRI StoryMaps web apps regarding each specific aspect of the island’s heritage. The goal of this paper is to discuss the importance of using such means for disseminating geoscientific information to the public, to describe the methods used and to give a brief presentation of its content. Full article

(This article belongs to the Special Issue Geosites as Tools for the Promotion and Conservation of Geoheritage)

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