Editorial

4 pages, 185 KiB

Open AccessEditorial

by Sergio Ferro and Marco Vocciante

Appl. Sci. 2021, 11(15), 6868; https://doi.org/10.3390/app11156868 - 26 Jul 2021

Viewed by 1376

In recent decades, increasing attention has been paid to the sustainability of products and processes, including activities aimed at environmental protection, site reclamation or treatment of contaminated effluents, as well as the valorization of waste through the recovery of resources. Although implemented with [...] Read more.

In recent decades, increasing attention has been paid to the sustainability of products and processes, including activities aimed at environmental protection, site reclamation or treatment of contaminated effluents, as well as the valorization of waste through the recovery of resources. Although implemented with ‘noble intentions’, these processes are often highly invasive, unsustainable and socially unacceptable, as they involve significant use of chemical products or energy. This Special Issue is aimed at collecting research activities focused on the development of new processes to replace the above-cited obsolete practices. Taking inspiration from real problems and the need to face real cases of contamination or prevent potentially harmful situations, the development and optimization of ‘smart’ solutions, i.e., sustainable not only from an environmental point of view but also economically, are discussed in order to encourage as much as possible their actual implementation. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

Research

Jump to: Editorial

12 pages, 1150 KiB

Open AccessArticle

Electrochemical Determination of Lead Using A Composite Sensor Obtained from Low-Cost Green Materials:Graphite/Cork

by Iasmin B. Silva, Danyelle Medeiros de Araújo, Marco Vocciante, Sergio Ferro, Carlos A. Martínez-Huitle and Elisama V. Dos Santos

Appl. Sci. 2021, 11(5), 2355; https://doi.org/10.3390/app11052355 - 06 Mar 2021

Cited by 14 | Viewed by 2225

Abstract

The purpose of this study was to develop an inexpensive, simple, and highly selective cork-modified carbon paste electrode for the determination of Pb(II) by differential pulse anodic stripping voltammetry (DPASV) and square-wave anodic stripping voltammetry (SWASV). Among the cork–graphite electrodes investigated, the one [...] Read more.

The purpose of this study was to develop an inexpensive, simple, and highly selective cork-modified carbon paste electrode for the determination of Pb(II) by differential pulse anodic stripping voltammetry (DPASV) and square-wave anodic stripping voltammetry (SWASV). Among the cork–graphite electrodes investigated, the one containing 70% w/w carbon showed the highest sensitivity for the determination of Pb(II) in aqueous solutions. Under SWASV conditions, its linear range and relative standard deviation are equal to 1–25 µM and 1.4%, respectively; the limit of detection complies with the value recommended by the World Health Organization. To optimize the operating conditions, the selectivity and accuracy of the analysis were further investigated by SWASV in acidic media. Finally, the electrode was successfully applied for the determination of Pb(II) in natural water samples, proving to be a sensitive electrochemical sensor that meets the stringent environmental control requirements. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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20 pages, 3861 KiB

Open AccessArticle

New Light on Phytoremediation: The Use of Luminescent Solar Concentrators

by Francesca Pedron, Martina Grifoni, Meri Barbafieri, Gianniantonio Petruzzelli, Elisabetta Franchi, Carmen Samà, Liliana Gila, Stefano Zanardi, Stefano Palmery, Antonio Proto and Marco Vocciante

Appl. Sci. 2021, 11(4), 1923; https://doi.org/10.3390/app11041923 - 22 Feb 2021

Cited by 10 | Viewed by 2667

Abstract

The latest developments in photovoltaic studies focus on the best use of the solar spectrum through Luminescent Solar Concentrators (LSC). Due to their structural characteristics, LSC panels allow considerable energy savings. This significant saving can also be of great interest in the remediation [...] Read more.

The latest developments in photovoltaic studies focus on the best use of the solar spectrum through Luminescent Solar Concentrators (LSC). Due to their structural characteristics, LSC panels allow considerable energy savings. This significant saving can also be of great interest in the remediation of contaminated sites, which nowadays requires green interventions characterized by high environmental sustainability. This study reported the evaluation of LSC panels in phytoremediation feasibility tests. Three plant species were used at a microcosm scale on soil contaminated by arsenic and lead. The experiments were conducted by comparing plants grown under LSC panels doped with Lumogen Red F305 (BASF) with plants grown under polycarbonate panels used for greenhouse construction. The results showed a higher production of biomass by the plants grown under the LSC panels. The uptake of the two contaminants by plants was the same in both the growing conditions, thus resulting in an increased total accumulation (defined as metal concentration times produced biomass) in plants grown under LSC panels, indicating an overall higher phytoextraction efficiency. This seems to confirm the potential that LSCs have to be building-integrated on greenhouse roofs, canopies, and shelters to produce electricity while increasing plants productivity, thus reducing environmental pollution, and increasing sustainability. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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12 pages, 1192 KiB

Open AccessArticle

Spray and Aerosolised pH-Neutral Electrochemically Activated Solution Reduces Salmonella Enteritidis and Total Bacterial Load on Egg Surface

by Sangay Tenzin, Sergio Ferro, Samiullah Khan, Permal Deo and Darren J. Trott

Appl. Sci. 2021, 11(2), 732; https://doi.org/10.3390/app11020732 - 13 Jan 2021

Cited by 2 | Viewed by 2096

Abstract

The effectiveness of sprayed and aerosolised pH-neutral electrochemically activated solutions (ECAS) containing 150 mg/L of free available chlorine in reducing total bacteria load and artificially inoculated Salmonella enterica serotype Enteritidis 11RX on eggs surfaces was investigated. Treatment groups included untreated control, sodium hypochlorite [...] Read more.

The effectiveness of sprayed and aerosolised pH-neutral electrochemically activated solutions (ECAS) containing 150 mg/L of free available chlorine in reducing total bacteria load and artificially inoculated Salmonella enterica serotype Enteritidis 11RX on eggs surfaces was investigated. Treatment groups included untreated control, sodium hypochlorite (positive control), sprayed and aerosolised water and sprayed and aerosolised ECAS. Sprayed ECAS (150 mg/L, 45 s) showed a significant reduction in total bacterial load (2.2 log reduction, p < 0.0001) and S. Enteritidis (5.4 log reduction, p < 0.0001) when compared with the untreated control. Aerosolised ECAS (120 s) was effective in reducing both the total bacterial load (1.4 log reduction, p < 0.01) and S. Enteritidis (4.2 log reduction, p = 0.0022). However, aerosolised ECAS (60 s) only significantly reduced S. Enteritidis counts (2.8 log reduction, p < 0.0008), indicating that a longer time for bacterial reduction during fogging sanitisation is needed. Tests performed with one egg per oscillating tray were more effective in reducing both the total bacterial load and the S. Enteritidis counts than those with three eggs per oscillating tray. Sprayed ECAS (45 s) and aerosolised ECAS (120 s) did not deteriorate the egg cuticle integrity (ΔE_ab^*), which was evaluated using Cuticle Blue dye solution and colour intensity measurement. Overall, both the reduction in total bacteria counts and S. Enteritidis from the egg surface and retention of cuticle integrity suggest that sprayed and aerosolised ECAS could be used as alternative sanitising approaches to improve the food safety aspect of table eggs. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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13 pages, 9797 KiB

Open AccessArticle

The Use of MgO Obtained from Serpentinite in the Synthesis of a Magnesium Potassium Phosphate Matrix for Radioactive Waste Immobilization

by Svetlana A. Kulikova, Sergey E. Vinokurov, Ruslan K. Khamizov, Natal’ya S. Vlasovskikh, Kseniya Y. Belova, Rustam K. Dzhenloda, Magomet A. Konov and Boris F. Myasoedov

Appl. Sci. 2021, 11(1), 220; https://doi.org/10.3390/app11010220 - 28 Dec 2020

Cited by 5 | Viewed by 2362

Abstract

Magnesium oxide is a necessary binding agent for the synthesis of a magnesium potassium phosphate (MPP) matrix based on MgKPO₄ × 6H₂O, which is promising for the solidification of radioactive waste (RW) on an industrial scale. The performed research is [...] Read more.

Magnesium oxide is a necessary binding agent for the synthesis of a magnesium potassium phosphate (MPP) matrix based on MgKPO₄ × 6H₂O, which is promising for the solidification of radioactive waste (RW) on an industrial scale. The performed research is devoted to finding a cost-effective approach to the synthesis of MPP matrix by using MgO with an optimal ratio of the quality of the binding agent and the cost of its production. A method for obtaining MgO from the widely available natural mineral serpentinite was proposed. The phase composition, particle morphology, and granulometric composition of MgO were studied. It was found that the obtained MgO sample, in addition to the target periclase phase, also contains impurities of brucite and hydromagnesite; however, after calcining at 1300 °C for 3 h, MgO transforms into a monophase state with a periclase structure with an average crystallite size of 62 nm. The aggregate size of the calcined MgO powder in an aqueous medium was about 55 μm (about 30 μm after ultrasonic dispersion), and the specific surface area was 5.4 m²/g. This powder was used to prepare samples of the MPP matrix, the compressive strength of which was about 6 MPa. The high hydrolytic stability of the MPP matrix was shown: the differential leaching rate of magnesium, potassium, and phosphorus from the sample on the 91st day of its contact with water does not exceed 1.6 × 10⁻⁵, 4.7 × 10⁻⁴ и 8.9 × 10⁻⁵ g/(cm²·day), respectively. Thus, it was confirmed that the obtained MPP matrix possesses the necessary quality indicators for RW immobilization. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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28 pages, 5513 KiB

Open AccessArticle

Barriers of Consumer Behavior for the Development of the Circular Economy: Empirical Evidence from Russia

by Svetlana Ratner, Inna Lazanyuk, Svetlana Revinova and Konstantin Gomonov

Appl. Sci. 2021, 11(1), 46; https://doi.org/10.3390/app11010046 - 23 Dec 2020

Cited by 20 | Viewed by 4074

Abstract

This paper contributes to the literature on sustainable consumption by in-depth analysis of the factors affecting the probability of 57 different practices of proenvironmental behavior (PEBs) in Russia. The set of studied PEBs includes not only popular energy-saving and waste-management practices but also [...] Read more.

This paper contributes to the literature on sustainable consumption by in-depth analysis of the factors affecting the probability of 57 different practices of proenvironmental behavior (PEBs) in Russia. The set of studied PEBs includes not only popular energy-saving and waste-management practices but also more circular patterns of plastic consumption, shopping, and city mobility. To study real and potential barriers to greening consumer behavior models, we conducted a survey of 623 respondents using a questionnaire developed based on a comparative analysis of similar studies conducted in other countries. The processing of the survey results was carried out using nonparametric statistics due to the absence of a normal distribution of the sample for most of the studied characteristics. The results of the study revealed that the main barriers to sustainable consumption in Russia are the lack of appropriate infrastructure as well as a lack of knowledge. Infrastructural barriers in some situations makes sustainable consumer behavior impossible or inconvenient (in this case, preference is given to other types of consumption), or in some cases necessitates spending additional time and money (then sustainable consumer behavior is not completely denied but practiced less often). Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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14 pages, 262 KiB

Open AccessArticle

Economic Valuation of Reducing Submerged Marine Debris in South Korea

by Se-Jun Jin, Young-Ju Kwon and Seung-Hoon Yoo

Appl. Sci. 2020, 10(17), 6086; https://doi.org/10.3390/app10176086 - 02 Sep 2020

Cited by 8 | Viewed by 1880

Abstract

Submerged marine debris (SMD) scattered between sea level and the bottom of the sea damages the habitats of marine life and threatens its growth in South Korea. The collection of SMD is more difficult and expensive than that of coastal and floating debris. [...] Read more.

Submerged marine debris (SMD) scattered between sea level and the bottom of the sea damages the habitats of marine life and threatens its growth in South Korea. The collection of SMD is more difficult and expensive than that of coastal and floating debris. The government is trying to achieve a 33% reduction in SMD by 2023 by expanding its collection, which requires huge additional investments and additional information about the economic value or benefits of the reduction. This article seeks to conduct an economic valuation of the reduction by employing contingent valuation (CV), which asks people to indicate their willingness to pay (WTP) for the reduction. A dichotomous choice CV survey was undertaken with 1000 households by a professional survey firm through person-to-person interviews during July 2019. Overall, people understood the CV questions well and reported the WTP responses for a hypothetical market successfully created with CV. Although 37.9% of interviewees stated zero WTP, the average of the yearly household WTP was estimated as 5523 Korean won (KRW) (USD 4.92). This value ensures statistical significance. The population’s WTP for the reduction would be KRW 110.30 billion (USD 99.75 million) per year over the next five years. It was found that the reduction is socially beneficial since the value was greater than the costs involved in the reduction. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

23 pages, 1926 KiB

Open AccessArticle

Towards Nearly Zero Energy and Environmentally Sustainable Agritourisms: The Effectiveness of the Application of the European Ecolabel Brand

by Laura Cirrincione, Maria La Gennusa, Giorgia Peri, Gianfranco Rizzo and Gianluca Scaccianoce

Appl. Sci. 2020, 10(17), 5741; https://doi.org/10.3390/app10175741 - 19 Aug 2020

Cited by 11 | Viewed by 2126

Abstract

Tourism represents an important economic driver in Italy, being responsible for approximately 13.2% of the total GDP (a value higher than the reference European average) and for nearly 10% of the regional GDP. Among the touristic sectors, the agritourist ones show a persistent [...] Read more.

Tourism represents an important economic driver in Italy, being responsible for approximately 13.2% of the total GDP (a value higher than the reference European average) and for nearly 10% of the regional GDP. Among the touristic sectors, the agritourist ones show a persistent growth, experiencing in 2019 a 6.7 point percentage improvement compared to the 2017 figures. Given this situation, the transition towards a low-carbon path, affecting the building sector for some time, should also involve agritourist buildings, through the release of EU directives, member state laws, and technical rules. On the other hand, agritourism sites could be awarded the Community EU Ecolabel. Unfortunately, awarding the EU environmental excellence brand implies the availability of several data on building energy behavior that should then be managed by complex evaluation tools. To overcome this issue, the use of the simplified ARERA (Italian Regulatory Authority for Energy Networks and Environment) technical datasheets, issued to assess environmental improvements consequent to energy efficiency interventions in the urban residential building stock, is proposed. The application of this tool totally avoids using building computer-based simulation models, thus facilitating the preparation of the EU Ecolabel request documentation by agritourism owners. Being awarded the Community EU Ecolabel also implies approaching a net zero energy condition because of a lower energy consumption and a minor recourse to fossil fuels. For this purpose, an application of an easy graphical method, previously developed for residential and commercial buildings, which visually represents improvements achievable by a given agritourism when implementing energy efficiency measures, is presented. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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17 pages, 2011 KiB

Open AccessArticle

Isolation and Characterization of a Novel Bacterium from the Marine Environment for Trichloroacetic Acid Bioremediation

by Mahshid Heidarrezaei, Hoofar Shokravi, Fahrul Huyop, Seyed Saeid Rahimian Koloor and Michal Petrů

Appl. Sci. 2020, 10(13), 4593; https://doi.org/10.3390/app10134593 - 02 Jul 2020

Cited by 21 | Viewed by 3891

Abstract

Halogenated compounds are an important class of environmental pollutants that are widely used in industrial chemicals such as solvents, herbicides, and pesticides. Many studies have been carried out to explore the biodegradation of these chemicals. Trichloroacetic acid (TCA) is one of the main [...] Read more.

Halogenated compounds are an important class of environmental pollutants that are widely used in industrial chemicals such as solvents, herbicides, and pesticides. Many studies have been carried out to explore the biodegradation of these chemicals. Trichloroacetic acid (TCA) is one of the main halogenated compounds that are carcinogenic to humans and animals. The bacterium was isolated from the northern coastline of Johor Strait. In this study, the ability of strain MH2 to biodegrade TCA was evaluated by a growth experiment and dehalogenase enzyme assay. The growth profile of the isolated strain was examined. The doubling time for L. boronitolerans MH2 was found to be 32 h. The release of chloride ion in the degradation process was measured at 0.33 × 10⁻³ ± 0.03 mol∙L⁻¹ after 96 h when the growth curve had reached its maximum within the late bacterial exponential phase. The results showed that the strain had a promising ability to degrade TCA by producing dehalogenase enzyme when cell-free extracts were prepared from growth on TCA as the sole carbon source with enzyme-specific activity, 1.1 ± 0.05 µmolCl⁻min⁻¹∙mg⁻¹ protein. Furthermore, the morphological, and biochemical aspects of the isolated bacterium were studied to identify and characterize the strain. The morphological observation of the isolated bacterium was seen to be a rod-shaped, Gram-positive, motile, heterotrophic, and spore-forming bacterium. The amplification of the 16S rRNA and gene analysis results indicated that the isolated bacterium had 98% similarity to Lysinibacillus boronitolerans. The morphological and biochemical tests supported the 16S rRNA gene amplification. To the best of the authors’ knowledge, this is the first reported case of this genus of bacteria to degrade this type of halogenated compound. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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20 pages, 3857 KiB

Open AccessArticle

Automated Chlorine Dosage in a Simulated Drinking Water Treatment Plant: A Real Case Study

by Javier Gámiz, Antoni Grau, Herminio Martínez and Yolanda Bolea

Appl. Sci. 2020, 10(11), 4035; https://doi.org/10.3390/app10114035 - 11 Jun 2020

Cited by 6 | Viewed by 7011

Abstract

In this paper, we present a simulator of a drinking water treatment plant. The model of the plant was based in hydraulic and matter transportation models. In order to not introduce more inaccuracies in the simulation, the control system was based in the [...] Read more.

In this paper, we present a simulator of a drinking water treatment plant. The model of the plant was based in hydraulic and matter transportation models. In order to not introduce more inaccuracies in the simulation, the control system was based in the real equipment deployed in the plant. This fact was the challenging part of the simulator, and an accurate design is presented in this research, wherein the sampling time had to be limited to interchange data between the SCADA in the plant and the simulator in real time. Due to the impossibility to stop the plant when testing the new control strategy, a simulator implemented the plant behavior under different extreme conditions. The validation of the simulator was performed with real data obtained from the plant. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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20 pages, 1677 KiB

Open AccessArticle

Optimal Manufacturing-Reconditioning Decisions in a Reverse Logistic System under Periodic Mandatory Carbon Regulation

by Sadok Turki, Soulayma Sahraoui, Christophe Sauvey and Nathalie Sauer

Appl. Sci. 2020, 10(10), 3534; https://doi.org/10.3390/app10103534 - 20 May 2020

Cited by 10 | Viewed by 2166

Abstract

Due to environmental concerns, firms are under increasing pressure to comply with legislations and to take up environmental strategies. This leads researchers and firms to develop new sustainable supply chains, where a new area has emerged for a manufacturing and reconditioning system. The [...] Read more.

Due to environmental concerns, firms are under increasing pressure to comply with legislations and to take up environmental strategies. This leads researchers and firms to develop new sustainable supply chains, where a new area has emerged for a manufacturing and reconditioning system. The originality of this work consists in simultaneously considering carbon emissions strategies, carbon tax and mandatory emission in a manufacturing-reconditioning system. The proposed system is composed of two parallel machines, a manufacturing stock, a reconditioning stock and a recovery inventory. In order to make the proposed green manufacturing system more realistic, it is assumed that manufactured (new products) and reconditioned products are distinguishable. The quantity of worn products (used products) depends on the sales in the previous periods, and the repair periods of the machines are stochastic and independent. The aim of this work is to determine the optimal capacities of manufacturing and reconditioning stocks that maximize the total profit, as well as the optimal value of worn products under two carbon emissions’ limitations. An evolutionary algorithm is developed, along with an efficient improvement method, to find the optimal value of decision variables. Ultimately, numerical results are provided to show the impact of the period of carbon limit and the worn products (returned products) on decision variables. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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21 pages, 1283 KiB

Open AccessArticle

Minimizing the Environmental Impact of Industrial Production: Evidence from South Korean Waste Treatment Investment Projects

by Olga A. Shvetsova and Jang Hee Lee

Appl. Sci. 2020, 10(10), 3489; https://doi.org/10.3390/app10103489 - 18 May 2020

Cited by 14 | Viewed by 4330

Abstract

This research deals with the theoretical and practical issues of investment support activities for industrial waste management in developed countries, based on the example of South Korea. The main goal of this research is the evaluation of waste treatment investment projects and understanding [...] Read more.

This research deals with the theoretical and practical issues of investment support activities for industrial waste management in developed countries, based on the example of South Korea. The main goal of this research is the evaluation of waste treatment investment projects and understanding their impact on the development of environmental policies. The problems of forming the sustainable systems for controlling the disposal of industrial wastes are being studied. The authors discuss the practical application of environmental policies and modern technologies of South Korean companies in the field of industrial waste processing. The approaches of waste investment project’s evaluation are applied and multi-criteria decision making (MCDM) methods were discussed for various cases and applications. Using MCDM methods, the authors study the effectiveness of investment projects in waste treatment activities in Korea. The analyses of MCDM methods are implemented in this research to provide some instructions on how to effectively apply these methods in waste treatment investment project analyses. Furthermore, the authors propose a combination of multi-criterial selection and interval preferences to evaluate waste treatment projects. The proposed approach improves the method of calculating economic efficiency based on a one-dimensional criterion and sensitivity analysis. The main results of this research perform the investment impact and risk-analysis on the environmental policies development. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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20 pages, 3742 KiB

Open AccessArticle

Sedimentation of Fractal Aggregates in Shear-Thinning Fluids

by Marco Trofa and Gaetano D’Avino

Appl. Sci. 2020, 10(9), 3267; https://doi.org/10.3390/app10093267 - 08 May 2020

Cited by 6 | Viewed by 2154

Abstract

Solid–liquid separation is a key unit operation in the wastewater treatment, generally consisting of coagulation and flocculation steps to promote aggregation and increase the particle size, followed by sedimentation, where the particles settle due to the effect of gravity. The sedimentation efficiency is [...] Read more.

Solid–liquid separation is a key unit operation in the wastewater treatment, generally consisting of coagulation and flocculation steps to promote aggregation and increase the particle size, followed by sedimentation, where the particles settle due to the effect of gravity. The sedimentation efficiency is related to the hydrodynamic behavior of the suspended particles that, in turn, depends on the aggregate morphology. In addition, the non-Newtonian rheology of sludges strongly affects the drag coefficient of the suspended particles, leading to deviations from the known settling behavior in Newtonian fluids. In this work, we use direct numerical simulations to study the hydrodynamic drag of fractal-shaped particles suspended in a shear-thinning fluid modeled by the power-law constitutive equation. The fluid dynamics governing equations are solved for an applied force with different orientations uniformly distributed over the unit sphere. The resulting particle velocities are interpolated to compute the aggregate dynamics and the drag correction coefficient. A remarkable effect of the detailed microstructure of the aggregate on the sedimentation process is observed. The orientational dynamics shows a rich behavior characterized by steady-state, bistable, and periodic regimes. In qualitative agreement with spherical particles, shear-thinning increases the drag correction coefficient. Elongated aggregates sediment more slowly than sphere-like particles, with a lower terminal velocity as the aspect ratio increases. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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15 pages, 1602 KiB

Open AccessArticle

Effects of an Eco-Friendly Sanitizing Wash on Spinach Leaf Bacterial Community Structure and Diversity

by Sangay Tenzin, Abiodun D. Ogunniyi, Sergio Ferro, Permal Deo and Darren J. Trott

Appl. Sci. 2020, 10(8), 2986; https://doi.org/10.3390/app10082986 - 24 Apr 2020

Cited by 3 | Viewed by 3405

Abstract

Ready-to-eat (RTE) spinach is considered a high-risk food, susceptible to colonization by foodborne pathogens; however, other microbial populations present on the vegetable surface may interact with foodborne pathogens by inhibiting/inactivating their growth. In addition, sanitizers applied to minimally processed salad leaves should not [...] Read more.

Ready-to-eat (RTE) spinach is considered a high-risk food, susceptible to colonization by foodborne pathogens; however, other microbial populations present on the vegetable surface may interact with foodborne pathogens by inhibiting/inactivating their growth. In addition, sanitizers applied to minimally processed salad leaves should not disrupt this autochthonous barrier and should be maintained throughout the shelf life of the product. This investigation aimed at comparing the effects of a pH neutral electrochemically activated solution (ECAS), a peroxyacetic acid (PAA)-based commercial sanitizer (Ecolab Tsunami^® 100), and tap water wash on the minimally processed spinach leaf microbiome profile for 10 days after washing. The bacterial microbiota composition on spinach samples was assessed by 16S rRNA pyrosequencing and downstream analyses. Predominant phyla observed in decreasing order of abundance were Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes corresponding with the dominant families Micrococcaceae, Clostridiales Family XII, Flavobacteriaceae, Pseudomonadaceae, and Burkholderiaceae. Bacterial species richness and evenness (alpha diversity) and bacterial community composition among all wash types were not significantly different. However, a significant difference was apparent between sampling days, corresponding to a loss of overall heterogeneity over time. Analysis of composition of microbiome (ANCOM) did not identify any amplicon sequence variants (ASVs) or families having significantly different abundance in wash types; however, differences (17 ASVs and five families) were found depending on sampling day. This was the first bacterial microbiome composition study focused on ECAS and PAA-based wash solutions. These wash alternatives do not significantly alter microbial community composition of RTE spinach leaves; however, storage at refrigerated temperature reduces bacterial species heterogeneity. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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11 pages, 3397 KiB

Open AccessArticle

Remediation of Copper Contaminated Soils Using Water Containing Hydrogen Nanobubbles

by Dongchan Kim and Junggeun Han

Appl. Sci. 2020, 10(6), 2185; https://doi.org/10.3390/app10062185 - 23 Mar 2020

Cited by 15 | Viewed by 3360

Abstract

This basic research study was undertaken to use ecofriendly nanobubbles that can improve the electrokinetic remediation of copper-contaminated soil, as well as to determine that remediation efficiency. The nanobubbles were generated by using pressurized hydrogen gas, and the quantity of hydrogen gas bubble [...] Read more.

This basic research study was undertaken to use ecofriendly nanobubbles that can improve the electrokinetic remediation of copper-contaminated soil, as well as to determine that remediation efficiency. The nanobubbles were generated by using pressurized hydrogen gas, and the quantity of hydrogen gas bubble that remained over 14 days was measured. The generated nanobubbles were used as an enhancer to remove a heavy metal on contaminated soil, and their applicability was confirmed. A batch test was used to compare the remediation effects of nanobubbles and distilled water on copper-contaminated soil. The results proved that the nanobubbles are a proper desorption agent for copper-contaminated sand and clay specimens. The solid–liquid ratio and the contact time for desorption of the sand and clay were then respectively determined. A large amount of effluent was obtained from electrokinetic remediation of the sand sample after applying the nanobubbles as an enhancer. The remediation efficiency demonstrated with sand proved to be higher than that for clay. This greater efficiency was attributed to a wider specific surface area, demonstrating the potential use of the nanobubbles as an enhancer for soil contaminated by copper with a large amount of effluent outflow. It was also assumed to be affected by the moving capability of the nanobubbles in the soil layer. Thus, the nanobubbled water can be used to improve the removal of heavy metals from contaminated soils. An ecofriendly enhancer for electrokinetic remediation with a relatively large void ratio and fast flowrate was confirmed by the nanobubbles. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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11 pages, 1468 KiB

Open AccessArticle

Chromium(III) Removal from Wastewater by Chitosan Flakes

by Loris Pietrelli, Iolanda Francolini, Antonella Piozzi, Maria Sighicelli, Ilaria Silvestro and Marco Vocciante

Appl. Sci. 2020, 10(6), 1925; https://doi.org/10.3390/app10061925 - 11 Mar 2020

Cited by 42 | Viewed by 4134

Abstract

Chitosan is very effective in removing metal ions through their adsorption. A preliminary investigation of the adsorption of chromium(III) by chitosan was carried out by means of batch tests as a function of contact time, pH, ion competition, and initial chromium(III) concentration. The [...] Read more.

Chitosan is very effective in removing metal ions through their adsorption. A preliminary investigation of the adsorption of chromium(III) by chitosan was carried out by means of batch tests as a function of contact time, pH, ion competition, and initial chromium(III) concentration. The rate of adsorption was rather rapid (t_1/2 < 18 min) and influenced by the presence of other metal ions. The obtained data were tested using the Langmuir and Freundlich isotherm models and, based on R² values, the former appeared better applicable than the latter. Chitosan was found to have an excellent loading capacity for chromium(III), namely 138.0 mg Cr per g of chitosan at pH = 3.8, but metal ions adsorption was strongly influenced by the pH. About 76% of the recovered chromium was then removed simply by washing the used chitosan with 0.1 M EDTA (Ethylenediaminetetraacetic acid) solution. This study demonstrates that chitosan has the potential to become an effective and low-cost agent for wastewater treatment (e.g., tannery waste) and in situ environmental remediation. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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19 pages, 5378 KiB

Open AccessArticle

Green Roofs as Effective Tools for Improving the Indoor Comfort Levels of Buildings—An Application to a Case Study in Sicily

by Laura Cirrincione, Maria La Gennusa, Giorgia Peri, Gianfranco Rizzo, Gianluca Scaccianoce, Giancarlo Sorrentino and Simona Aprile

Appl. Sci. 2020, 10(3), 893; https://doi.org/10.3390/app10030893 - 29 Jan 2020

Cited by 25 | Viewed by 3183

Abstract

In the line of pursuing better energy efficiency in human activities that would result in a more sustainable utilization of resources, the building sector plays a relevant role, being responsible for almost 40% of both energy consumption and the release of pollutant substances [...] Read more.

In the line of pursuing better energy efficiency in human activities that would result in a more sustainable utilization of resources, the building sector plays a relevant role, being responsible for almost 40% of both energy consumption and the release of pollutant substances in the atmosphere. For this purpose, techniques aimed at improving the energy performances of buildings’ envelopes are of paramount importance. Among them, green roofs are becoming increasingly popular due to their capability of reducing the (electric) energy needs for (summer) climatization of buildings, hence also positively affecting the indoor comfort levels for the occupants. Clearly, reliable tools for the modelling of these envelope components are needed, requiring the availability of suitable field data. Starting with the results of a case study designed to estimate how the adoption of green roofs on a Sicilian building could positively affect its energy performance, this paper shows the impact of this technology on indoor comfort and energy consumption, as well as on the reduction of direct and indirect CO₂ emissions related to the climatization of the building. Specifically, the ceiling surface temperatures of some rooms located underneath six different types of green roofs were monitored. Subsequently, the obtained data were used as input for one of the most widely used simulation models, i.e., EnergyPlus, to evaluate the indoor comfort levels and the achievable energy demand savings of the building involved. From these field analyses, green roofs were shown to contribute to the mitigation of the indoor air temperatures, thus producing an improvement of the comfort conditions, especially in summer conditions, despite some worsening during transition periods seeming to arise. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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19 pages, 1174 KiB

Open AccessArticle

Which Influencing Factors Could Reduce Ecological Consumption? Evidence from 90 Countries for the Time Period 1996–2015

by Shuai Zhang, Dajian Zhu, Jiaping Zhang and Lilian Li

Appl. Sci. 2020, 10(2), 678; https://doi.org/10.3390/app10020678 - 18 Jan 2020

Cited by 12 | Viewed by 3472

Abstract

In the “full world” and Anthropocene, global ecological consumption is beyond natural capital’s regenerative and absorptive abilities, and ecological consumption of humanity has to be reduced to have an ecologically sustainable future. To achieve the goal of ecological sustainability, influencing factors that could [...] Read more.

In the “full world” and Anthropocene, global ecological consumption is beyond natural capital’s regenerative and absorptive abilities, and ecological consumption of humanity has to be reduced to have an ecologically sustainable future. To achieve the goal of ecological sustainability, influencing factors that could reduce ecological consumption need to be explored. Based on three panel datasets for the time period 1996–2015, this paper estimates the impacts of urbanization, renewable energy consumption, service industries, and internet usage on ecological consumption for all 90 sample countries, the 42 developed countries, and the 48 developing countries. Education and income are taken as control variables in the panel regressions. As a consumption-side indicator, the ecological footprint is selected to measure ecological consumption. The estimations find that (1) urbanization has negative impacts for all sample countries and the developed countries, and it is insignificant for the developing countries, (2) renewable energy consumption and service industries have negative impacts for all of the three samples, and (3) internet usage has lagged negative impacts for all sample countries, and it is an independent and significant force of reducing ecological consumption in the developing countries rather than the developed countries. It is found that there is a positive linear relationship, an inversed U-shaped relationship, and a U-shaped relationship between ecological consumption and income in all sample countries, the developed countries, and the developing countries, respectively. The estimated results provide guidance for evidence-based policymaking on reducing ecological consumption. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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15 pages, 16279 KiB

Open AccessArticle

The Impact of Virtual Water on Sustainable Development in Gansu Province

by Weixuan Wang, Jan F. Adamowski, Chunfang Liu, Yujia Liu, Yongkai Zhang, Xueyan Wang, Haohai Su and Jianjun Cao

Appl. Sci. 2020, 10(2), 586; https://doi.org/10.3390/app10020586 - 13 Jan 2020

Cited by 7 | Viewed by 2318

Abstract

The concept of virtual water, as a new approach for addressing water shortage and safety issues, can be applied to support sustainable development in water-scarce regions. Using the input-output method, the direct and the complete water use coefficients of industries categorized as primary, [...] Read more.

The concept of virtual water, as a new approach for addressing water shortage and safety issues, can be applied to support sustainable development in water-scarce regions. Using the input-output method, the direct and the complete water use coefficients of industries categorized as primary, secondary, or tertiary, and the spatial flow patterns of the inter-provincial trade in the Gansu province region of China, were explored. The results show that in 2007, 2010, and 2012 the direct and complete water use coefficients of the primary industries were the greatest among the three industry categories, with direct water use coefficients of 1545.58, 882.28, and 762.16, respectively, and complete water use coefficients of 1692.22, 1005.38, and 873.44, respectively; whereas, the direct and complete water use coefficient values of the tertiary industry category were the lowest, with direct water use coefficients of 16.65, 7.74, and 66.89 for 2007, 2010, and 2012, respectively, and complete water use coefficients of 65.46, 66.89, and 72.81 for 2007, 2010, and 2012, respectively. In addition, study results suggest that the volume of virtual water supplied to Gasnu province’s local industries has decreased annually, while virtual water exports from the province have increased annually, with the primary industry accounting for 95% of virtual water output. Overall, the virtual water of Gansu province in 2010 showed a net output trend, with a total output of 0.506 billion m³, while in 2007 and 2012 it showed a net input trend with a total input of 0.104 and 1.235 billion m³, respectively. Beijing, Shanghai, Guangdong, Ningxia and other water-scarce areas were the main input, or import source for Gansu’s virtual water; during the years studied, these provinces imported more than 50 million m³ individually. Based on these results, it is clear that under the current structure, virtual water is mainly exported to the well-developed coastal areas and their adjacent provinces or other water-abundant regions. Therefore, Gansu province should (1) adjust the industrial structure and develop water-saving and high-tech industries; (2) adjust the current trade pattern to reduce virtual water output while increasing its input to achieve balanced economic development and water resource security. Full article

(This article belongs to the Special Issue Sustainable Environmental Solutions)

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