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Materials and Technologies Used in Wastewater Treatment

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: closed (30 September 2021) | Viewed by 52564

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Special Issue Editors

Prof. Dr. Maria Isabel Capela

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Guest Editor

Department of Environment and Planning, Centre for Environmental and Marine Studies (CESAM), Institute of Environment and Development (IDAD), University of Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro, Portugal
Interests: water and wastewater treatment; biological processes to obtain added-value products (biopolymers, volatile acids); anaerobic digestion for the production of green energy (biomethane, biohydrogen, biohythane); biodegradation of toxic and complex compounds; chemical oxidation of bio-recalcitrant compounds using nanomaterials

Dr. Mohammadreza Kamali

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Assistant Guest Editor

Department of Chemical Engineering, Process and Environmental Technology Lab, KU Leuven, Campus De Nayer-2860, Sint-Katelijne-Waver, Belgium
Interests: development of engineered materials for advanced catalytic wastewater treatment systems; optimization of biological treatment technologies using sustainable materials; valorisation of industrial and municipal solid wastes; sustainability assessment and life-cycle analysis of advanced technologies; development of the environmental quality standards
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Special Issue Information

This Special Issue is related to “Materials and Technologies Used in Wastewater Treatment”.

Despite enormous efforts to develop efficient technologies for industrial wastewater treatment, the selection of the most sustainable process among the possible alternatives is still a formidable task. The quality of final effluents discharged from numerous industrial activities has been the subject of much debate in the past decades to improve the performance of the processes used, whether through physical-chemical processes, biological processes, or a combination of these. On the other hand, industries around the world, particularly those that generate recalcitrant and emerging pollutants, are fighting for their economic profitability. In addition, awareness concerning the environment and the use of clean technologies is growing worldwide.

All researchers working in the field are cordially invited to contribute original research papers or reviews to this Special Issue of Molecules, which reports on the design, synthesis, and evaluation of novel materials for wastewater treatment, advanced processes capable of addressing key wastewater treatment issues (e.g., the removal of recalcitrant and toxic contaminants), the development of efficient and sustainable technologies, and the development of engineered biological systems to synthesize commodities and provide services beyond waste treatment.

Prof. Dr. Maria Isabel Capela
Guest Editor

Dr. Mohammadreza Kamali
Assistant Guest Editor

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Keywords

wastewater treatment
recalcitrant compounds
sustainable technologies
renewable energy
advanced technologies
novel materials for treatment
circular economy

Published Papers (13 papers)

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Research

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15 pages, 4300 KiB

Open AccessArticle

ZnO/γ-Fe₂O₃/Bentonite: An Efficient Solar-Light Active Magnetic Photocatalyst for the Degradation of Pharmaceutical Active Compounds

by Mohammadreza Kamali, Yongtao Xue, Mohammadreza Khalaj, Bodhi Laats, Ruben Teunckens, Matthias Verbist, Maria Elisabete V. Costa, Isabel Capela, Lise Appels and Raf Dewil

Molecules 2022, 27(10), 3050; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27103050 - 10 May 2022

Cited by 5 | Viewed by 1726

Abstract

For applications related to the photocatalytic degradation of environmental contaminants, engineered nanomaterials (ENMs) must demonstrate not only a high photocatalytic potential, but also a low tendency to agglomeration, along with the ability to be easily collected after use. In this manuscript, a two-step process was implemented for the synthesis of ZnO, ZnO/Bentonite and the magnetic ZnO/γ-Fe₂O₃/Bentonite nanocomposite. The synthesized materials were characterized using various techniques, and their performance in the degradation of pharmaceutical active compounds (PhACs), including ciprofloxacin (CIP), sulfamethoxazole (SMX), and carbamazepine (CBZ) was evaluated under various operating conditions, namely the type and dosage of the applied materials, pH, concentration of pollutants, and their appearance form in the medium (i.e., as a single pollutant or as a mixture of PhACs). Among the materials studied, ZnO/Bentonite presented the best performance and resulted in the removal of ~95% of CIP (5 mg/L) in 30 min, at room temperature, near-neutral pH (6.5), ZnO/Bentonite dosage of 0.5 g/L, and under solar light irradiation. The composite also showed a high degree of efficiency for the simultaneous removal of CIP (~98%, 5 mg/L) and SMX (~97%, 5 mg/L) within 30 min, while a low degradation of ~5% was observed for CBZ (5 mg/L) in a mixture of the three PhACs. Furthermore, mechanistic studies using different types of scavengers revealed the formation of active oxidative species responsible for the degradation of CIP in the photocatalytic system studied with the contribution of h⁺ (67%), OH (18%), and ·O₂⁻ (10%), and in which holes (h⁺) were found to be the dominant oxidative species. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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12 pages, 2367 KiB

Open AccessArticle

Degradation of Neonicotinoids and Caffeine from Surface Water by Photolysis

by Alexandra Raschitor, Alberto Romero, Sandra Sanches, Vanessa J. Pereira, Joao G. Crespo and Javier Llanos

Molecules 2021, 26(23), 7277; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26237277 - 30 Nov 2021

Cited by 3 | Viewed by 1666

Abstract

Along with rapid social development, the use of insecticides and caffeine-containing products increases, a trend that is also reflected in the composition of surface waters. This study is focused on the phototreatment of a surface water containing three neonicotinoids (imidacloprid, thiamethoxam, and clothianidin) and caffeine. Firstly, the radiation absorption of the target pollutants and the effect of the water matrix components were evaluated. It was observed that the maximum absorption peaks appear at wavelengths ranging from 246 to 274 nm, and that the water matrix did not affect the efficiency of the removal of the target pollutants. It was found that the insecticides were efficiently removed after a very short exposure to UV irradiation, while the addition of hydrogen peroxide was needed for an efficient caffeine depletion. The electrical energy per order was estimated, being the lowest energy required (9.5 kWh m⁻³ order⁻¹) for the depletion of thiamethoxan by indirect photolysis, and a concentration of hydrogen peroxide of 5 mg dm⁻³. Finally, a preliminary evaluation on the formation of by-products reveals that these compounds play a key role in the evolution of the ecotoxicity of the samples, and that the application of direct photolysis reduces the concentration of these intermediates. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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13 pages, 13323 KiB

Open AccessArticle

Application of the Swimming Pool Backwash Water Recovery System with the Use of Filter Tubes

by Waldemar Studziński, Wojciech Poćwiardowski and Weronika Osińska

Molecules 2021, 26(21), 6620; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26216620 - 31 Oct 2021

Cited by 5 | Viewed by 2365

Abstract

During the operation of swimming pools, large losses of water from the backwash of swimming pool filters are observed. This water is often discharged into sewers or used to sprinkle sports grounds. The aim of the research was to design and build an installation for purification and recovery of backwash water (BWW). It consists of flocculation, pre-filtration, and ultrafiltration based on filter tubes and ozone disinfection. Backwash water treatment installation contributes to purification and improvement of water quality. The effectiveness of the removal of microbial contamination with the use of the system was over 99%. The high efficiency of removing physicochemical impurities was also achieved. Water turbidity was reduced from 96.9 NTU to 0.13 NTU. After using the system, the oxidability of water decreased from 6.26 mg O₂∙dm⁻³ to 0.4 mg O₂∙dm⁻³. When using the system, a reduction of total organic carbon by 80% was also noticed. After the treatment process, water meets the strict criteria and can be returned to the pool system of water as fresh water with parameters of supply water—directly to the overflow tank. It has been shown that up to 96% of water can be recovered with the technology. The cost comparison showed annual savings of over EUR 9000. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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14 pages, 1806 KiB

Open AccessArticle

Combining Coagulation and Electrocoagulation with UVA-LED Photo-Fenton to Improve the Efficiency and Reduce the Cost of Mature Landfill Leachate Treatment

by Javier Tejera, Daphne Hermosilla, Antonio Gascó, Carlos Negro and Ángeles Blanco

Molecules 2021, 26(21), 6425; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26216425 - 25 Oct 2021

Cited by 10 | Viewed by 1536

Abstract

This study focused on the reduction of the treatment cost of mature landfill leachate (LL) by enhancing the coagulation pre-treatment before a UVA-LED photo-Fenton process. A more efficient advanced coagulation pretreatment was designed by combining conventional coagulation (CC) and electro-coagulation (EC). Regardless of the order in which the two coagulations were applied, the combination achieved more than 73% color removal, 80% COD removal, and 27% SUVA removal. However, the coagulation order had a great influence on both final pH and total dissolved iron, which were key parameters for the UVA-LED photo-Fenton post-treatment. CC (pH = 5; 2 g L⁻¹ of FeCl₃6H₂O) followed by EC (pH = 5; 10 mA cm⁻²) resulted in a pH of 6.4 and 100 mg L⁻¹ of dissolved iron, whereas EC (pH = 4; 10 mA cm⁻²) followed by CC (pH = 6; 1 g L⁻¹ FeCl₃6H₂O) led to a final pH of 3.4 and 210 mg L⁻¹ dissolved iron. This last combination was therefore considered better for the posterior photo-Fenton treatment. Results at the best cost-efficient [H₂O₂]:COD ratio of 1.063 showed a high treatment efficiency, namely the removal of 99% of the color, 89% of the COD, and 60% of the SUVA. Conductivity was reduced by 17%, and biodegradability increased to BOD₅:COD = 0.40. With this proposed treatment, a final COD of only 453 mg O₂ L⁻¹ was obtained at a treatment cost of EUR 3.42 kg COD⁻¹. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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19 pages, 3660 KiB

Open AccessArticle

Green Tea Waste as an Efficient Adsorbent for Methylene Blue: Structuring of a Novel Adsorbent Using Full Factorial Design

by Marwa El-Azazy, Ahmed S. El-Shafie and Bayan Al-Shaikh Yousef

Molecules 2021, 26(20), 6138; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26206138 - 11 Oct 2021

Cited by 17 | Viewed by 1988

Abstract

Adsorptive removal of methylene blue (MB) from contaminated water samples was achieved using green tea waste (GTW). Adsorption of MB onto raw (RGTW) and thermally treated waste (TTGTW250–TTGTW500) was explored. The performance of the tested adsorbents was assessed in terms of percentage removal of MB (%R) and adsorption capacity (qe, mg/g). A full factorial design (FFD) was employed to optimize the adsorption of MB onto both RGTW and TTGTW500. Four factors were studied: pH, adsorbent dose (AD), dye concentration (DC), and contact time (CT). Value for %R of 96.58% and 98.07% were obtained using RGTW and TTGTW500, respectively. FT-IR and Raman analyses were used to study the surfaces of the prepared adsorbents, and the IR spectrum showed the existence of a variety of functionalities on the surfaces of both the RGTW and thermally treated samples. BET analysis showed the presence of mesopores and macropores in the case of RGTW and micropores in the case of thermally processed adsorbents. Equilibrium studies indicated that the Freundlich isotherm best described the adsorption of MB onto both adsorbents. The maximum adsorption capacity (q_max) was found to be 68.28 and 69.01 mg/g for RGTW and TTGTW500, respectively, implying the superior capacity of TTGTW500 in removing MB. Adsorption of MB was found to proceed via chemisorption (RGTW) and physisorption (TTGTW500), as indicated by the Dubinin–Radushkevich (D-R) isotherm. A pseudo-second order (PSO) model best demonstrated the kinetics of the MB adsorption onto both adsorbents. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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12 pages, 29838 KiB

Open AccessArticle

Removal of Tannic Acid Stabilizes CuO Nanoparticles from Aqueous Media by PAFC: Effect of Process Conditions and Water Chemistry

by Rizwan Khan, Muhammad Ali Inam and Kang Hoon Lee

Molecules 2021, 26(18), 5615; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26185615 - 16 Sep 2021

Viewed by 1465

Abstract

The increased utilization of CuO nanoparticles (CuO NPs) in various fields has raised concerns about their discharge into water containing a wide range of organic ligands. Moreover, the adsorption of these ligands can stabilize the CuO NPs in drinking water treatment plants. Thus, their removal from potable water is important to mitigate the risk to humans. The present study explored the efficacy of the coagulation–sedimentation (C/S) process for the removal of tannic acid (TA)-stabilized CuO NPs using polyaluminum ferric chloride (PAFC) as a coagulant. Moreover, the influence of process conditions (stirring speed) and water chemistry (i.e., pH and ionic strength (IS)) were also investigated to determine their impact on removal. The results showed that stirring speed in the reaction phase significantly affected the removal due to increased flocculation compared with stirring speed in the mixing phase. In addition, pH and IS affect the colloidal stability and removal efficiency of CuO NPs. A relatively better removal performance (<99%) of CuO NPs was found at lower coagulant dosage in the pH range 6–8. The addition of organic ligands reversed the surface charge potential and enhanced the colloidal stability of CuO NPs, resulting in the destabilization of TA-CuO NPs, thereby reducing the optimum PAFC dosage for removal. By contrast, the IS above the critical coagulation concentration decreased the removal efficiency due to inhibition of the ionic activity of PAFC hydrolysate in the aqueous environment. Fourier transform infrared findings of TA-CuO NPs composite flocs suggest that the primary removal mechanism might be mediated via the combined effect of neutralization, complexation as well as adsorption. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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13 pages, 4502 KiB

Open AccessArticle

Preparation of Sorbents Containing Straetlingite Phase from Zeolitic By-Product and Their Performance for Ammonium Ion Removal

by Agnė Mikelionienė, Danutė Vaičiukynienė, Aras Kantautas, Algirdas Radzevičius and Katarzyna Zarębska

Molecules 2021, 26(10), 3020; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26103020 - 19 May 2021

Cited by 1 | Viewed by 1519

Abstract

In this study, straetlingite-based sorbents were used for NH₄⁺ ion removal from a synthetic aqueous solution and from the wastewater of an open recirculation African catfish farming system. This study was performed using column experiments with four different filtration rates (2, 5, 10, and 15 mL/min). It was determined that breakthrough points and sorption capacity could be affected by several parameters such as flow rate and mineral composition of sorption materials. In the synthetic aqueous solution, NH₄⁺ removal reached the highest sorption capacity, i.e., 0.341 mg/g with the S30 sorbent at a filtration rate of 10 mL/min and an initial concentration of 10 mg/L of NH₄⁺ ions. It is important to emphasize that, in this case, the Ce/C0 ratio of 0.9 was not reached after 420 min of sorption. It was also determined that the NH₄⁺ sorption capacity was influenced by phosphorus. In the wastewater, the NH₄⁺ sorption capacity was almost seven times lower than that in the synthetic aqueous solution. However, it should be highlighted that the P sorption capacity reached 0.512 mg/g. According to these results, it can be concluded that straetlingite-based sorbents can be used for NH₄⁺ ion removal from a synthetic aqueous solution, as well as for both NH₄⁺ and P removal from industrial wastewater. In the wastewater, a significantly higher sorption capacity of the investigated sorbents was detected for P than for NH₄⁺. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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22 pages, 7977 KiB

Open AccessArticle

Biochar of Spent Coffee Grounds as Per Se and Impregnated with TiO₂: Promising Waste-Derived Adsorbents for Balofloxacin

by Marwa El-Azazy, Ahmed S. El-Shafie and Hagar Morsy

Molecules 2021, 26(8), 2295; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26082295 - 15 Apr 2021

Cited by 27 | Viewed by 3161

Abstract

Biochars (BC) of spent coffee grounds, both pristine (SCBC) and impregnated with titanium oxide (TiO₂@SCBC) were exploited as environmentally friendly and economical sorbents for the fluroquinolone antibiotic balofloxacin (BALX). Surface morphology, functional moieties, and thermal stabilities of both adsorbents were scrutinized using SEM, EDS, TEM, BET, FTIR, Raman, and TG/dT analyses. BET analysis indicated that the impregnation with TiO₂ has increased the surface area (50.54 m²/g) and decreased the pore size and volume. Batch adsorption experiments were completed in lights of the experimental set-up of Plackett-Burman design (PBD). Two responses were maximized; the % removal (%R) and the adsorption capacity (q_e, mg/g) as a function of four variables: pH, adsorbent dosage (AD), BALX concentration ([BALX]), and contact time (CT). %R of 68.34% and 91.78% were accomplished using the pristine and TiO₂@SCBC, respectively. Equilibrium isotherms indicated that Freundlich model was of a perfect fit for adsorption of BALX onto both adsorbents. Maximum adsorption capacity (q_max) of 142.55 mg/g for SCBC and 196.73 mg/g for the TiO₂@SCBC. Kinetics of the adsorption process were best demonstrated using the pseudo-second order (PSO) model. The adsorption-desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 66.32% after the fifth cycles. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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16 pages, 5021 KiB

Open AccessArticle

Effects of Ornamental Plant Density and Mineral/Plastic Media on the Removal of Domestic Wastewater Pollutants by Home Wetlands Technology

by Luis Carlos Sandoval-Herazo, Alejandro Alvarado-Lassman, María Cristina López-Méndez, Albino Martínez-Sibaja, Alberto A. Aguilar-Lasserre, Sergio Zamora-Castro and José Luis Marín-Muñiz

Molecules 2020, 25(22), 5273; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25225273 - 12 Nov 2020

Cited by 9 | Viewed by 2713

Abstract

Wastewater treatment (WWT) is a priority around the world; conventional treatments are not widely used in rural areas owing to the high operating and maintenance costs. In Mexico, for instance, only 40% of wastewater is treated. One sustainable option for WWT is through the use of constructed wetlands (CWs) technology, which may remove pollutants using cells filled with porous material and vegetation that works as a natural filter. Knowing the optimal material and density of plants used per square meter in CWs would allow improving their WWT effect. In this study, the effect of material media (plastic/mineral) and plant density on the removal of organic/inorganic pollutants was evaluated. Low (three plants), medium (six plants) and high (nine plants) densities were compared in a surface area of 0.3 m² of ornamental plants (Alpinia purpurata, Canna hybrids and Hedychium coronarium) used in polycultures at the mesocosm level of household wetlands, planted on the two different substrates. Regarding the removal of contaminants, no significant differences were found between substrates (p ≥ 0.05), indicating the use of plastic residues (reusable) is an economical option compared to typical mineral materials. However, differences (p = 0.001) in removal of pollutants were found between different plant densities. For both substrates, the high density planted CWs were able to remove COD in a range of 86–90%, PO₄-P 22–33%, NH₄-N in 84–90%, NO₃-N 25–28% and NO₂-N 38–42%. At medium density, removals of 79–81%, 26–32, 80–82%, 24–26%, and 39–41%, were observed, whereas in CWs with low density, the detected removals were 65–68%, 20–26%, 79–80%, 24–26% and 31–40%, respectively. These results revealed that higher COD and ammonia were removed at high plant density than at medium or low densities. Other pollutants were removed similarly in all plant densities (22–42%), indicating the necessity of hybrid CWs to increase the elimination of PO₄-P, NO₃-N and NO₂-N. Moreover, high density favored 10 to 20% more the removal of pollutants than other plant densities. In addition, in cells with high density of plants and smaller planting distance, the development of new plant shoots was limited. Thus, it is suggested that the appropriate distance for this type of polyculture plants should be from 40 to 50 cm in expansion to real-scale systems in order to take advantage of the harvesting of species in these and allow species of greater foliage, favoring its growth and new shoots with the appropriate distance to compensate, in the short time, the removal of nutrients. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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10 pages, 2109 KiB

Open AccessArticle

Pre-Treatment Methods for Regeneration of Spent Activated Carbon

by Sang Youp Hwang, Gi Bbum Lee, Ji Hyun Kim, Bum Ui Hong and Jung Eun Park

Molecules 2020, 25(19), 4561; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25194561 - 06 Oct 2020

Cited by 15 | Viewed by 2334

Abstract

Spent activated carbon (SAC) usually exhibits a low specific surface area due to its high ash contents. In this study, pre-treatments, such as heat and acid treatments, were optimized to improve this feature. The heat pre-treatment did not reduce the ash content, nor did it increase the surface area. Because metallic ions adsorbed in SACs turn into ash upon the heat treatment. In the acid pre-treatment, the volatiles and fixed carbon were increased with decreasing ash contents. In this study, it was found that the surface area increase was correlated with the ratio between fixed carbon and ash. Among the pre-treatment methods, the combined heat and acid pre-treatment method highly increased the ratio, and therefore led to the surface area increase. Additionally, the acid pre-treatment was carried out using different types of acid (organic and inorganic acids) solutions to further improve the surface areas. The organic acid treatment caused a significant structural collapse compared to the inorganic acid treatment, decreasing the surface area. In particular, H₃PO₄ effectively removed ashes adsorbed on the activated carbon surface and regenerated the exhausted activated carbon. Both the heat and acid pre-treatments before chemical activation resulted in the positive effects such as strong desorption of pollutants and ashes within the internal structure of the activated carbon. Therefore, the regeneration introduced in this study is methodically the best method to regenerate SAC and maintain a stable structure. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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Review

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40 pages, 5724 KiB

Open AccessReview

A Brief History of Colour, the Environmental Impact of Synthetic Dyes and Removal by Using Laccases

by Leidy D. Ardila-Leal, Raúl A. Poutou-Piñales, Aura M. Pedroza-Rodríguez and Balkys E. Quevedo-Hidalgo

Molecules 2021, 26(13), 3813; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26133813 - 22 Jun 2021

Cited by 176 | Viewed by 12990

Abstract

The history of colour is fascinating from a social and artistic viewpoint because it shows the way; use; and importance acquired. The use of colours date back to the Stone Age (the first news of cave paintings); colour has contributed to the social and symbolic development of civilizations. Colour has been associated with hierarchy; power and leadership in some of them. The advent of synthetic dyes has revolutionized the colour industry; and due to their low cost; their use has spread to different industrial sectors. Although the percentage of coloured wastewater discharged by the textile; food; pharmaceutical; cosmetic; and paper industries; among other productive areas; are unknown; the toxic effect and ecological implications of this discharged into water bodies are harmful. This review briefly shows the social and artistic history surrounding the discovery and use of natural and synthetic dyes. We summarise the environmental impact caused by the discharge of untreated or poorly treated coloured wastewater to water bodies; which has led to physical; chemical and biological treatments to reduce the colour units so as important physicochemical parameters. We also focus on laccase utility (EC 1.10.3.2), for discolouration enzymatic treatment of coloured wastewater, before its discharge into water bodies. Laccases (p-diphenol: oxidoreductase dioxide) are multicopper oxidoreductase enzymes widely distributed in plants, insects, bacteria, and fungi. Fungal laccases have employed for wastewater colour removal due to their high redox potential. This review includes an analysis of the stability of laccases, the factors that influence production at high scales to achieve discolouration of high volumes of contaminated wastewater, the biotechnological impact of laccases, and the degradation routes that some dyes may follow when using the laccase for colour removal Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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26 pages, 1962 KiB

Open AccessReview

Nanotechnology in Wastewater Management: A New Paradigm Towards Wastewater Treatment

by Keerti Jain, Anand S. Patel, Vishwas P. Pardhi and Swaran Jeet Singh Flora

Molecules 2021, 26(6), 1797; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26061797 - 23 Mar 2021

Cited by 134 | Viewed by 12911

Abstract

Clean and safe water is a fundamental human need for multi-faceted development of society and a thriving economy. Brisk rises in populations, expanding industrialization, urbanization and extensive agriculture practices have resulted in the generation of wastewater which have not only made the water dirty or polluted, but also deadly. Millions of people die every year due to diseases communicated through consumption of water contaminated by deleterious pathogens. Although various methods for wastewater treatment have been explored in the last few decades but their use is restrained by many limitations including use of chemicals, formation of disinfection by-products (DBPs), time consumption and expensiveness. Nanotechnology, manipulation of matter at a molecular or an atomic level to craft new structures, devices and systems having superior electronic, optical, magnetic, conductive and mechanical properties, is emerging as a promising technology, which has demonstrated remarkable feats in various fields including wastewater treatment. Nanomaterials encompass a high surface to volume ratio, a high sensitivity and reactivity, a high adsorption capacity, and ease of functionalization which makes them suitable for application in wastewater treatment. In this article we have reviewed the techniques being developed for wastewater treatment using nanotechnology based on adsorption and biosorption, nanofiltration, photocatalysis, disinfection and sensing technology. Furthermore, this review also highlights the fate of the nanomaterials in wastewater treatment as well as risks associated with their use. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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26 pages, 2294 KiB

Open AccessReview

Technologies Employed in the Treatment of Water Contaminated with Glyphosate: A Review

by Patricio J. Espinoza-Montero, Carolina Vega-Verduga, Paulina Alulema-Pullupaxi, Lenys Fernández and Jose L. Paz

Molecules 2020, 25(23), 5550; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25235550 - 26 Nov 2020

Cited by 38 | Viewed by 5116

Abstract

Glyphosate [N-(phosphonomethyl)-glycine] is a herbicide with several commercial formulations that are used generally in agriculture for the control of various weeds. It is the most used pesticide in the world and comprises multiple constituents (coadjutants, salts, and others) that help to effectively reach the action’s mechanism in plants. Due to its extensive and inadequate use, this herbicide has been frequently detected in water, principally in surface and groundwater nearest to agricultural areas. Its presence in the aquatic environment poses chronic and remote hazards to human health and the environment. Therefore, it becomes necessary to develop treatment processes to remediate aquatic environments polluted with glyphosate, its metabolites, and/or coadjutants. This review is focused on conventional and non-conventional water treatment processes developed for water polluted with glyphosate herbicide; it describes the fundamental mechanism of water treatment processes and their applications are summarized. It addressed biological processes (bacterial and fungi degradation), physicochemical processes (adsorption, membrane filtration), advanced oxidation processes—AOPs (photocatalysis, electrochemical oxidation, photo-electrocatalysis, among others) and combined water treatment processes. Finally, the main operating parameters and the effectiveness of treatment processes are analyzed, ending with an analysis of the challenges in this field of research. Full article

(This article belongs to the Special Issue Materials and Technologies Used in Wastewater Treatment)

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