Research

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13 pages, 1887 KiB

Open AccessArticle

Synergistic Removal of β-Hexachlorocyclohexane from Water via Microorganism–Plant Technology and Analysis of Bacterial Community Characteristics

by Huijun Shi, Shuang Luo, Yanpeng Liang, Litang Qin, Honghu Zeng and Xiaohong Song

Water 2023, 15(13), 2328; https://doi.org/10.3390/w15132328 - 22 Jun 2023

Viewed by 894

Abstract

In recent years, β-Hexachlorocyclohexane (β-HCH) has been detected frequently in water, seriously threatening human health and ecological balance. To explore the effects of different treatment groups on the removal of β-HCH in experimental water and the response of microbial [...] Read more.

In recent years, β-Hexachlorocyclohexane (β-HCH) has been detected frequently in water, seriously threatening human health and ecological balance. To explore the effects of different treatment groups on the removal of β-HCH in experimental water and the response of microbial community structure in the system, three strains of β-HCH-degrading bacteria—Ochrobactrum sp. (Och1, Och2) and Pseudomonas sp. (Pse1)—combined with Canna were selected for microbial, plant, and microbe–plant repair hydroponic experiments, respectively. Solid-phase extraction combined with GC-ECD and high-throughput sequencing determined the β-HCH content and bacterial community in water and Canna tissues. The results showed that when β-HCH stress concentrations were 10 μg·L⁻¹ and 100 μg·L⁻¹, Och1 and Pse1 showed the best degradation performance (33.49% and 60.02%, respectively). Following this, the three degrading strains were combined with Canna. Under the two β-HCH stress concentrations, the combination of Och1–Canna showed the highest β-HCH removal efficiency (96.74% and 99.06%). At the same time, we measured the concentration of β-HCH in Canna tissues and found that Och1 had a better removal effect on β-HCH in water and that the addition of Pse1 may significantly improve the absorption capacity of β-HCH in Canna roots. In addition, the relative abundance of Methophilic bacteria in experimental water and Canna root samples increased significantly after the inoculation of degrading bacteria, suggesting that Methophilic bacteria may be vital in degrading benzene-ring-containing substances. The results of this research can provide a theoretical basis and technical support for the prevention and control of the non-point source pollution of organic pesticides. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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26 pages, 8043 KiB

Open AccessArticle

Photocatalytic Degradation of Methylene Blue Dye from Wastewater by Using Doped Zinc Oxide Nanoparticles

by Shreya Modi, Virendra Kumar Yadav, Abdelfattah Amari, Abeer Yousef Alyami, Amel Gacem, Hamed N. Harharah and Madhusudan Hiraman Fulekar

Water 2023, 15(12), 2275; https://doi.org/10.3390/w15122275 - 17 Jun 2023

Cited by 17 | Viewed by 3745

Abstract

ZnO is a semiconductor material that has important physical and chemical properties, which are frequently and significantly enhanced by the addition of impurities, such as doping. A study of the structural properties of pristine and functionalized (i.e., doped with Antimony and Tungsten) ZnO [...] Read more.

ZnO is a semiconductor material that has important physical and chemical properties, which are frequently and significantly enhanced by the addition of impurities, such as doping. A study of the structural properties of pristine and functionalized (i.e., doped with Antimony and Tungsten) ZnO nanoparticles has been conducted for the photocatalyst-based degradation of methylene blue (MB) dye under both Ultraviolet (UV) and solar light. Authors have used a 1% concentration of dopant for doping purposes. The synthesized materials were characterized for structural analysis, functional group identification, spectroscopic measurements, and morphological examination using X-ray diffraction (XRD), Fourier transform-infrared (FTIR), UV-Vis spectroscopy (UV-Vis), and Field emission scanning electron microscope (FESEM) techniques. XRD analysis confirmed that the synthesized-doped materials retained the wurtzite hexagonal structure with a purity of 99%. Transmission electron microscope (TEM) analysis data reveals the average size of pure ZnO-NPs was found to be 7 nm; after doping the size was found to be increased to 18 nm and 9.55 nm, respectively, for ZnO-W and ZnO-Sb. As per FESEM analysis results, minor morphological changes were observed after doping. The Ultraviolet Differential reflectance spectroscopy UV-DRS study revealed the confirmation of ZnO doping with antimony and tungsten, which exhibited a blue shift. The decrease in the band-gap on doping makes the ZnO-NPs more efficient for photocatalytic applications. The photocatalytic efficiency of pristine and doped ZnO-NPs catalysts for methylene blue photocatalytic degradation (PCD) was analyzed under both UV and solar irradiation. This study analyzed the effect of pH, nano-photocatalyst dose, and initial dye concentration (ICD) on the PCD of MB. The obtained analytical results showed that the ideal conditions for the PCD of MB dye are as follows: pH = 9, the quantity of the nano-photocatalyst used was 300 mg/L, and an initial MB dye dose of 10 ppm. These conditions lead to a PCD of about 91% of the MB dye by using ZnO-Sb nano-photocatalyst on exposure to solar radiation. The reusability study also revealed the stability of nano-photocatalysts. The current research may pave the way for the removal of hazardous dyes from wastewater discharged by many industries. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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16 pages, 5072 KiB

Open AccessArticle

Bioscorodite Production from As(III) and Fe(II) Salts under Oxidizing and Acidic Conditions of Trichoderma atroviride Culture

by Jesús Adriana Ramírez-Castillo, Refugio Rodríguez-Vázquez, Ricardo Aguilar-López and José Roberto Zúñiga-Silva

Water 2023, 15(10), 1905; https://doi.org/10.3390/w15101905 - 17 May 2023

Cited by 1 | Viewed by 1166

Abstract

Arsenic (As) contamination of groundwater is widespread and significantly affects drinking water, posing a threat to public health due to its classification as a human carcinogen. Arsenic (As) can be removed from contaminated water using sustainable technologies (e.g., biotechnological processes). The process of [...] Read more.

Arsenic (As) contamination of groundwater is widespread and significantly affects drinking water, posing a threat to public health due to its classification as a human carcinogen. Arsenic (As) can be removed from contaminated water using sustainable technologies (e.g., biotechnological processes). The process of removing Arsenic from water through reactions with iron under acidic and oxidizing conditions in a fungal broth has been proposed alongside the production of bioscorodite (FeAsO₄·2H₂O) crystals by Trichoderma atroviride culture. This ascomycete was selected based on tests with three other fungi (Aspergillus niger, and the basidiomycetes, Postia placenta, and Phanerochaete chrysosporium) because it decreased the pH to 2.2, raised the redox potential (Eh) to 207 mV, and was the quickest to produce 0.39 µg/L of H₂O₂ in a modified Wunder medium. The Eh was further increased to 324.80 mV under improved fungal culture conditions, selected using a 2³⁻¹ fractional factorial design (FFD). The fungal broth was then used for bioscorodite production by adding Fe(III)/As(III) salts and scorodite seeds at 92 °C for 21 h. Scorodite seeds and bioscorodite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Arsenic was determined in solution by atomic absorption spectrophotometry (AAS), and a 73% reduction in the initial As concentration (0.30 g/100 mL) was observed after bioscorodite production. Bioscorodite production under appropriate fungal culture conditions could be an option for sustainable As removal from water. The production of H₂O₂ by the fungus resulted in the oxidation of As(III) into As(V) and acidification of the culture broth, which created the necessary conditions for the production of bioscorodite without the need for chemical acids or oxidants. This approach is environmentally friendly and cost effective, making it a promising alternative for the treatment of arsenic-contaminated water. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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15 pages, 3332 KiB

Open AccessFeature PaperArticle

An Integrated Approach for the Recovery of Sn from Used Water Adsorbents

by Efthimia Kaprara, Evangelia Daskalopoulou, Konstantinos Simeonidis and Manassis Mitrakas

Water 2023, 15(1), 97; https://doi.org/10.3390/w15010097 - 28 Dec 2022

Cited by 1 | Viewed by 1596

Abstract

This research examined a scenario for the recovery of a high-capacity Cr(VI) adsorbent, consisting of Sn₆O₄(OH)₄, after reaching its operational lifetime. To accomplish this target, a sequence of processes involving the spent adsorbent’s decomposition, the separation of [...] Read more.

This research examined a scenario for the recovery of a high-capacity Cr(VI) adsorbent, consisting of Sn₆O₄(OH)₄, after reaching its operational lifetime. To accomplish this target, a sequence of processes involving the spent adsorbent’s decomposition, the separation of Sn/Cr ions, and Sn₆O₄(OH)₄ reconstruction was investigated. Characterization of the saturated adsorbent indicated its extended oxidation to SnO₂ during its use according to the occurring Cr(VI) to Cr(III) reduction mechanism, which is responsible for the loading of 19 mg Cr/g. To decompose saturated adsorbent, the optimized process involved the dissolution by HCl using a solid concentration of 10 g/L, a solid to acid mass proportion of 1:20, an increase of the temperature at 75 °C. Such conditions brought a dissolution rate of more than 95% and 92.5%, respectively, of the total Sn and Cr in the spent adsorbent. Then, separation of Cr was succeeded by the addition of hydrazine, which acts as a reducing agent for the transformation of Sn(IV) to Sn(II); the precipitation of Cr(III) at pH 3, and the reconstruction of Sn₆O₄(OH)₄ in a second step after increasing pH to 7. The recovered adsorbent stabilized a higher percentage of Sn(II) than the initial material, which explains the improvement of the removal efficiency by 50% in the Cr(VI) adsorption capacity. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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13 pages, 2682 KiB

Open AccessArticle

Cu(II) Adsorption from Aqueous Solution onto Poly(Acrylic Acid/Chestnut Shell Pigment) Hydrogel

by Hui Zhang, Guo-Wei Li, Wei Feng and Zeng-Yu Yao

Water 2022, 14(21), 3500; https://doi.org/10.3390/w14213500 - 02 Nov 2022

Cited by 7 | Viewed by 1684

Abstract

Powerful adsorbents for heavy-metal removal from wastewater are attractive due to the growing effluent of industries. Developing hydrogels is a current research interest in heavy-metal adsorption from aqueous solutions. We prepared a novel melanin-based hydrogel from renewable chestnut shell pigment and acrylic acid [...] Read more.

Powerful adsorbents for heavy-metal removal from wastewater are attractive due to the growing effluent of industries. Developing hydrogels is a current research interest in heavy-metal adsorption from aqueous solutions. We prepared a novel melanin-based hydrogel from renewable chestnut shell pigment and acrylic acid by radical polymerization free from a traditional crosslinker. The synthesized material was characterized by Fourier transform infrared spectroscopy and scanning electron microscope. Its Cu(II)-adsorption performance from the water was evaluated by equilibrium isotherms, kinetics, and thermodynamics. The results indicate that: (1) The dry hydrogel showed a porous structure with a network of interconnected spindle-shaped bars, which makes it feasible to serve as an adsorbent; (2) The kinetic adsorption data followed both the pseudo-first-order and the pseudo-second-order models and both physical and chemical processes involved in the Cu(II) removal; (3) Cation exchanges with H⁺ from COOH and phenolic OH groups and with NH₄⁺ from –COONH₄ were likely the primary mechanisms of Cu(II) chemisorption adsorption onto the poly(AA/CSP) as forms of Cu²⁺ and CuOH⁺; (4) The equilibrium data were well fitted by the Langmuir isotherm with the maximum monolayer adsorption capacity of 200.3 mg/g; (5) The adsorption was a spontaneous and exothermic process co-driven by enthalpy and entropy. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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21 pages, 1805 KiB

Open AccessArticle

Acid Mine Drainage Treatment Using a Process Train with Laterite Mine Waste, Concrete Waste, and Limestone as Treatment Media

by Casey Oliver A. Turingan, Kristina S. Cordero, Aileen L. Santos, Gillian Sue L. Tan, Carlito B. Tabelin, Richard D. Alorro and Aileen H. Orbecido

Water 2022, 14(7), 1070; https://doi.org/10.3390/w14071070 - 29 Mar 2022

Cited by 9 | Viewed by 3604

Abstract

Without treatment, the harmful effects of acid mine drainage (AMD) lead to the destruction of surrounding ecosystems, including serious health impacts to affected communities. Active methods, like chemical neutralization, are the most widely used approach to AMD management. However, these techniques require constant [...] Read more.

Without treatment, the harmful effects of acid mine drainage (AMD) lead to the destruction of surrounding ecosystems, including serious health impacts to affected communities. Active methods, like chemical neutralization, are the most widely used approach to AMD management. However, these techniques require constant inputs of energy, chemicals, and manpower, which become unsustainable in the long-term. One promising and sustainable alternative for AMD management is to use passive treatment systems with locally available and waste-derived alkalinity-generating materials. In this study, the treatment of synthetic AMD with laterite mine waste (LMW), concrete waste, and limestone in a successive process train was elucidated, and the optimal process train configuration was determined. Six full factorial analyses were performed following a constant ratio of 0.75 mL AMD/g media with a 15-min retention time. The evolution of the pH, redox potential (Eh), total dissolved solids (TDS), heavy metals concentration, and sulfates concentrations were monitored as the basis for evaluating the treatment performance of each run. LMW had the highest metal and sulfates removal, while concrete waste caused the largest pH increase. A ranking system was utilized in which each parameter was normalized based on the Philippine effluent standards (DENR Administrative Order (DAO) 2016–08 and 2021–19). Run 4 (Limestone-LMW-Concrete waste) showed the best performance, that is, the pH increased from 1.35 to 8.08 and removed 39% Fe, 94% Ni, 72% Al, and 52% sulfate. With this, the process train is more effective to treat AMD, and the order of the media in treatment is significant. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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6 pages, 16959 KiB

Open AccessArticle

Long-Term Sustainability of Using Hemodialyzers to Inexpensively Provide Pathogen-Free Water to Remote Villages Lacking Electricity

by Friedrich K. Port, David A. Goodkin, Jochen G. Raimann, Joseph M. Boaheng, Seth Johnson, Mathieu Lamolle, Linda Donald and Nathan W. Levin

Water 2022, 14(3), 471; https://doi.org/10.3390/w14030471 - 04 Feb 2022

Cited by 1 | Viewed by 1794

Abstract

The provision of clean water to remote communities is a major goal of both the World Health Organization and the United Nations. We report on the long-term sustainability of filter-sterilizing polluted water in remote villages in Ghana that lack electricity. Contaminated water pumped [...] Read more.

The provision of clean water to remote communities is a major goal of both the World Health Organization and the United Nations. We report on the long-term sustainability of filter-sterilizing polluted water in remote villages in Ghana that lack electricity. Contaminated water pumped several times a week via a gasoline pump into a 1000 L elevated tank is filtered through polysulfone hemodialyzers on demand. The 3 nm fiber pore size rejects all bacteria, parasites, and viruses. Villagers flush organic matter from the dialyzers thrice daily to maintain a flow of up to 250 L/h. Having previously reported a 73% reduction in diarrheal episodes, we now address system sustainability. After passing through the hemodialyzer filters, a fecally polluted water source remains consistently free of pathogens even after the system has been in place for >1 year in most villages. Filters are easily replaced when needed. Daily cost for unlimited clean water is less than USD 2.22 per village over five years. Villagers have continued to independently fill the tank and flush the system, because they appreciate the clean water and health benefits. We demonstrate that over 2–6 years this system providing pathogen-free drinking water can be maintained independently by villagers for long-term sustainability. It does not require electricity nor disinfectants to be added to the product water and is ready for far broader application in similarly remote settings. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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18 pages, 6149 KiB

Open AccessArticle

Field Test of In Situ Groundwater Treatment Applying Oxygen Diffusion and Bioaugmentation Methods in an Area with Sustained Total Petroleum Hydrocarbon (TPH) Contaminant Flow

by Artem Demenev, Nikolay Maksimovich, Vadim Khmurchik, Gennadiy Rogovskiy, Anatoliy Rogovskiy and Alexey Baryshnikov

Water 2022, 14(2), 192; https://doi.org/10.3390/w14020192 - 11 Jan 2022

Cited by 4 | Viewed by 3351

Abstract

Contamination of groundwater by petroleum hydrocarbons is a widespread environmental problem in many regions. Contamination of unsaturated and saturated zones could also pose a significant risk to human health. The main purpose of the study was to assess the efficiency of biodegradation of [...] Read more.

Contamination of groundwater by petroleum hydrocarbons is a widespread environmental problem in many regions. Contamination of unsaturated and saturated zones could also pose a significant risk to human health. The main purpose of the study was to assess the efficiency of biodegradation of total petroleum hydrocarbon (TPH) in situ, in an area with loam and sandy loam soils, and to identify features and characteristics related to groundwater treatment in an area with a persistent flow of pollutants. We used methods of biostimulation (oxygen as stimulatory supplement) and bioaugmentation to improve water quality. Oxygen was added to the groundwater by diffusion through silicone tubing. The efficiency of groundwater treatment was determined by detailed monitoring. Implementation of the applied measure resulted in an average reduction in TPH concentration of 73.1% compared with the initial average concentration (4.33 mg/L), and in the local area, TPH content was reduced by 95.5%. The authors hope that this paper will contribute to a better understanding of the topic of groundwater treatment by in situ biodegradation of TPH. Further studies on this topic are particularly needed to provide more data and details on the efficiency of groundwater treatment under adverse geological conditions. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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15 pages, 1911 KiB

Open AccessArticle

Influence of Particle Size of River Sand on the Decontamination Process in the Slow Sand Filter Treatment of Micro-Polluted Water

by Xuemei Ji, Cui Zhao, Yufeng Lv, Jifu Yang and Bin Li

Water 2022, 14(1), 100; https://doi.org/10.3390/w14010100 - 04 Jan 2022

Cited by 3 | Viewed by 2883

Abstract

Slow sand filters (SSFs) have been widely used in the construction of water plants in rural areas. It is necessary to find river sand of suitable particle size to improve SSF treatment of micro-polluted water so as to ensure the effective and long-term [...] Read more.

Slow sand filters (SSFs) have been widely used in the construction of water plants in rural areas. It is necessary to find river sand of suitable particle size to improve SSF treatment of micro-polluted water so as to ensure the effective and long-term operation of these plants. In this study, SSF1^# (particle size of 0.1–0.5 mm), SSF2^# (particle size of 0.5–1 mm), and SSF3^# (particle size of 1–1.5 mm) were selected. The physical absorption, COD_Mn and NH₄⁺-N removal effect, and microbial community were analyzed. According to Langmuir and Freundlich adsorption model fitting, the smaller the particle size of the river sand, the more pollutants are adsorbed under the same conditions. SSF1^# has the shortest membrane-forming time, highest COD_Mn and NH₄⁺-N removal rate, and highest Shannon estimator, indicating that there are more abundant microbial species in the biofilm. Mesorhizobium, Pannonibacter, Pseudoxanthomonas, Aquabacterium, Devosia, and other bacteria have different proportions in each system, each forming its own stable biological chain system. The effluent quality of the three SSFs can meet drinking water standards. However, river sand with a particle size range of 0.1–0.5 mm is easily blocked, and thus the recommended size range for SSF is 0.5–1 mm. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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19 pages, 3952 KiB

Open AccessArticle

A Biological Method of Treating Surface Water Contaminated with Industrial Waste Leachate

by Justyna Zamorska and Izabela Kiełb-Sotkiewicz

Water 2021, 13(24), 3644; https://doi.org/10.3390/w13243644 - 17 Dec 2021

Cited by 4 | Viewed by 3188

Abstract

The progressive chemicalization of all areas of everyday life and the development of the industry cause the appearance of various types of pollutants, both in groundwater and surface waters. Kalina Pond (Świętochłowice, Poland) is an example of a degraded water reservoir as a [...] Read more.

The progressive chemicalization of all areas of everyday life and the development of the industry cause the appearance of various types of pollutants, both in groundwater and surface waters. Kalina Pond (Świętochłowice, Poland) is an example of a degraded water reservoir as a result of many years of activity, among others hard coal mines, storing metallurgical waste by zinc plants, and the activities of the Hajduki Chemical Plants from Chorzów. Inadequate securing of waste heaps resulted in the penetration of pollutants, i.e., phenol, petroleum compounds, PAHs, cyanides, and heavy metals. The aim of the research was to determine the suitability of biopreparations for the removal of pollutants. The research used a bacterial biopreparation from BioArcus, “DBC plus type R5”, to remove petroleum compounds and phenol. Then, in order to restore the microbiological balance, “ACS ODO-1” from the biopreparation was used. The research was carried out in laboratory conditions, using three variants: direct dosing of biopreparations, dosing of biopreparations previously activated by multiplication on the medium, and dosing of biopreparations into water after filtration on a diatomite bed. The optimal method of recultivating water from a reservoir was to filter this water through a diatomite bed and then dose the multiplied bacteria. After the filtration process, the obtained percentage of TOC reduction allowed for the rapid development of microorganisms from the biopreparation, despite the 100 times lower dose used. In addition, the application of lyophilized biopreparation to contaminated water resulted in a very fast biodegradation effect of pollutants, despite the high concentration of numerous toxic compounds. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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13 pages, 2154 KiB

Open AccessArticle

Disinfection of Dental Chair Water Using Aqueous Chlorine Dioxide

by Li-Lin Wei, Chan-Chih Hu, Chu-Wei Hsu, Chun-Wei Pen, Li-Yu Chen, Yu-Chun Yu, James R. Carey, Hao-Chang Yin and Shan-Shue Wang

Water 2021, 13(23), 3442; https://doi.org/10.3390/w13233442 - 04 Dec 2021

Cited by 1 | Viewed by 3593

Abstract

Chlorine dioxide is a safe, environmentally friendly disinfecting agent. In this study, aqueous chlorine dioxide (ACD) was used to improve the water quality of dental chairs. However, chlorine dioxide is readily released from ACD solutions under open atmosphere conditions. Described herein is a [...] Read more.

Chlorine dioxide is a safe, environmentally friendly disinfecting agent. In this study, aqueous chlorine dioxide (ACD) was used to improve the water quality of dental chairs. However, chlorine dioxide is readily released from ACD solutions under open atmosphere conditions. Described herein is a water purification and disinfection system using ACD. The system was designed, fabricated, and integrated into an existing dental chair water system. This system is referred to as an ACD dental chair. Because ClO₂ readily degasses from ACD, there needs to be a way to maintain and measure the ACD solution in real time. In our studies, we found that pH and oxidation-reduction potential (ORP) change as a function of chlorine dioxide concentration and are easily controlled and measured. The dosing of the ACD was designed to begin at 800 mV and stop dosing at 810 mV in the ACD dental chair. Through use of this continuous monitoring and automatic dosing system, the water ORP was controlled between 800 and 860 mV. This range is the effective concentration of chlorine dioxide that is without chlorine-like odor and microorganism growth. The ACD dental chair controlled the total bacterial count to <5 CFU/mL and the chlorite concentration was less than 0.0004 mg/L, meeting legal standards of Taiwan, the USA, and China. In addition to the application of ACD in dental chairs, it may also be used in closed water systems for food, cosmetics, beverages, and other industries. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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Review

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34 pages, 8530 KiB

Open AccessReview

Nanocomposite Zinc Oxide-Based Photocatalysts: Recent Developments in Their Use for the Treatment of Dye-Polluted Wastewater

by Abayomi D. Folawewo and Muhammad D. Bala

Water 2022, 14(23), 3899; https://doi.org/10.3390/w14233899 - 30 Nov 2022

Cited by 10 | Viewed by 2821

Abstract

This review highlights current developments in utilising zinc oxide (ZnO) composite materials as photocatalysts. Systematic analyses of the various synthetic methods for producing ZnO-based hetero-structured materials, the variety of methods for their characterisation, their mechanisms of action, and widespread applications for the degradation [...] Read more.

This review highlights current developments in utilising zinc oxide (ZnO) composite materials as photocatalysts. Systematic analyses of the various synthetic methods for producing ZnO-based hetero-structured materials, the variety of methods for their characterisation, their mechanisms of action, and widespread applications for the degradation of pollutants are discussed. Structure/activity relationships and methods of improving on some of the recognised shortcomings of ZnO-based nanomaterial catalysts are also presented. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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24 pages, 3305 KiB

Open AccessReview

A Recent and Systemic Approach Towards Microbial Biodegradation of Dyes from Textile Industries

by Heli Patel, Virendra Kumar Yadav, Krishna Kumar Yadav, Nisha Choudhary, Haresh Kalasariya, M. Mujahid Alam, Amel Gacem, Mohammed Amanullah, Hala A. Ibrahium, Jae-Woo Park, Sungmin Park and Byong-Hun Jeon

Water 2022, 14(19), 3163; https://doi.org/10.3390/w14193163 - 08 Oct 2022

Cited by 33 | Viewed by 6507

Abstract

The textile industry generated a series of synthetic dyestuffs that threatened environmental protection. Azo dyes, widely utilized in textile, paper, fruit, leathers, cosmeceuticals and pharmaceutical fields, account for most of the dyestuffs made. Since they have colour fastness properties, stability, and susceptibility to [...] Read more.

The textile industry generated a series of synthetic dyestuffs that threatened environmental protection. Azo dyes, widely utilized in textile, paper, fruit, leathers, cosmeceuticals and pharmaceutical fields, account for most of the dyestuffs made. Since they have colour fastness properties, stability, and susceptibility to oxidation, existing effluent treatment methods cannot entirely strip different dyes from effluents. Under certain environmental factors, bacteria decolourize and degrade dyes. The treatment process is cheap, environmentally safe, and can be used on various dyes. However, textile plant wastewater can produce many polluting chemicals and dyes. Environmental legislation is increasingly being enacted to regulate mainly azo-based dyes in the environment. The potential of the microbes for the decolourization of dyes and metabolizing them is long-known knowledge. The toxic components of dyes challenge a potential threat to all the living forms of life. Though both natural and synthetic dyes are used for the colourization of textiles, only synthetic ones are challenging to decolourize. Microbial-based bioremediation of dyes has been studied and reviewed primarily to accelerate dye degradation. The various piece of the literature revealed that the majority of these dye removal microbes belong to mainly white-rot fungi, a consortium of anaerobic bacteria. In addition to this, there are several (genetically engineered microorganisms) GEMs that remediate dyes efficiently. Here in the current review, the authors have tried to bridge the existing gap in the bioremediation of dyestuff. Moreover, the authors have also tried to provide the latest trend in this field. This study will surely benefit the industries and researchers related to dyestuffs by maintaining eco-friendly approaches. Full article

(This article belongs to the Special Issue Application of Sustainable Chemical and Biological Methods for Pollutants Removal from Water)

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