Field Of Wastewater Treatment Research Articles

Silver‐anchored dendrimer efficiently Light‐drive conversion of p‐nitrophenol

AbstractEfficient use of solar energy for photocatalytic organic synthesis and degradation of organic matter is one of the most promising ways to solve energy shortage and environmental pollution. Silver/sulfur‐doped polyimide (Ag/SPI) was successfully prepared by anchoring silver nanoparticles on sulfur doped polyimide with dendriform structure by an open‐loop and closed‐loop method. Through the analysis of the structure, morphology and photoelectric properties by different characteristics, it is found that the anchoring of silver nanoparticles greatly reduces the electron‐hole recombination rate of SPI, and the cyclic stability is relatively good, and the electrons generated by photoexcitation can participate in the reduction of p‐nitrophenol more. Therefore, the activity of degradation of organic pollutants was greatly improved under the irradiation of visible light. At 5 minutes, the degradation rate of p‐nitrophenol reached 100 %, and the only product p‐nitrophenol was generated. The reaction time was 12 times that of SPI without anchored metal particles. The Ag/SPI dual‐function catalyst provides a new idea for the application of p‐nitrophenol wastewater treatment and the conversion of p‐aminophenol and provides a new reference direction for the field of organic wastewater treatment and organic synthesis.

Chlorination of Emerging Contaminants for Application in Potable Wastewater Reuse: Disinfection Byproduct Formation, Estrogen Activity, and Cytotoxicity.

With increasing water scarcity, many utilities are considering the potable reuse of wastewater as a source of drinking water. However, not all chemicals are removed in conventional wastewater treatment, and disinfection byproducts (DBPs) can form from these contaminants when disinfectants are applied during or after reuse treatment, especially if applied upstream of advanced treatment processes to control biofouling. We investigated the chlorination of seven priority emerging contaminants (17β-estradiol, estrone, 17α-ethinylestradiol, bisphenol A (BPA), diclofenac, p-nonylphenol, and triclosan) in ultrapure water, and we also investigated the impact of chlorination on real samples from different treatment stages of an advanced reuse plant to evaluate the role of chlorination on the associated cytotoxicity and estrogenicity. Many DBPs were tentatively identified via liquid chromatography (LC)- and gas chromatography (GC)-high resolution mass spectrometry, including 28 not previously reported. These encompassed chlorinated, brominated, and oxidized analogs of the parent compounds as well as smaller halogenated molecules. Chlorinated BPA was the least cytotoxic of the DBPs formed but was highly estrogenic, whereas chlorinated hormones were highly cytotoxic. Estrogenicity decreased by ∼4-6 orders of magnitude for 17β-estradiol and estrone following chlorination but increased 2 orders of magnitude for diclofenac. Estrogenicity of chlorinated BPA and p-nonylphenol were ∼50% of the natural/synthetic hormones. Potential seasonal differences in estrogen activity of unreacted vs reacted advanced wastewater treatment field samples were observed.

Bisulfite boosts the reduction activity of zero-valent iron towards p-nitrophenol under anoxic conditions

Zero-valent iron (ZVI) is widely used in the field of wastewater treatment and groundwater remediation, but it suffers from low reactivity due to the surface passivation layer. In the present work, bisulfite was used as an additive to enhance the reduction activity of ZVI under anoxic conditions. It was found that the reaction kinetic constant of p-nitrophenol reduction in ZVI/bisulfite process was approximately 132 times higher than that by ZVI alone. Bisulfite could dissolve and reduce some iron oxide on the ZVI surface, resulting in the exposure of more active sites like Fe0 and Fe(II) for p-nitrophenol reduction through direct electron transfer. Common substances in water had no effects on p-nitrophenol degradation by ZVI/bisulfite process, but phosphate suppressed ZVI corrosion seriously. This work provides a simple, cost-effective and environmental-friendly method to improve the reducing activity of ZVI under anoxic conditions.

Modelling biofilm development: The importance of considering the link between EPS distribution, detachment mechanisms and physical properties

In industry, treatments against biofilms need to be optimized and, in the wastewater treatment field, biofilm composition needs to be controlled. Therefore, describing the biochemical and physical structures of biofilms is now required to better understand the influence of operating parameters and treatment on biofilms. The present study aims to investigate how growth conditions influence EPS composition, biofilm physical properties and volume detachment using a 1D biofilm model. Two types of EPS are considered in the present model, proteins and polysaccharides. The main hypotheses are that: (i) the production of polysaccharides occurs mainly under strong nutrient limitation(s) while the production of proteins is coupled to both the substrate uptake rate and the lysis process; (ii) the local biofilm porosity depends on the local biofilm composition. Both volume and surface detachment occur in biofilms and volume detachment extent depends on the biofilm local cohesion and thus on the local composition of biofilms for a given shear stress.The model is based on experimental trends and aims to represent these observations on the basis of biochemical and physical processes. Four case studies covering a wide range of contrasting growth conditions such as different COD/N ratios, applied SOLR and shear stresses are investigated. The model predicts how the biochemical and physical biofilm structures change as a result of contrasting growth conditions. More precisely simulation results are in good agreement with the main experimental observations reported in the literature, such as: (i) a strong nitrogen limitation of growth induces an important accumulation of polysaccharides leading to a more porous and homogenous biofilm, (ii) a high applied surface organic loading load allows to obtain a high biofilm thickness, (iii) a strong shear stress applied during the biofilm growth leads to a reduction of the biofilm thickness and to a consolidation of the biofilm structure. Overall, this model represents a relevant decision tool for the selection of appropriate enzymatic treatments in the context of negative biofilm control. From our results, it appears that protease based treatments should be more appropriate for biofilms developed under low COD/N ratios (about 20 gCOD/gN) whereas both glucosidases and proteases based treatments should be more appropriate for biofilms developed under high COD/N ratio (about 70 gCOD/gN). In addition, the model could be useful for other applications such as resource recovery in biofilms or granules, and help to better understand biological membrane fouling.

Muscovite clay for methylene blue removal: advanced optimization and Al-guided breakthroughs-an independent application from prior antibiotic removal investigation.

This study evaluates the efficacy of muscovite mineral clay as an adsorbent for removing Methylene Blue (MB) from water-based solutions. The research examined the impact of initial MB concentration, adsorbent mass, and time on the MB removal process. Two modeling techniques, namely Box-Behnken design with response surface methodology (BBD-RSM) and Artificial Neural Network (ANN), were employed to accurately predict the MB removal efficiency. The RSM and ANN models yielded satisfactory results in estimating MB removal efficiency. To further enhance the optimization process, conventional and techno-economic methods were implemented. The conventional method aimed to maximize dye removal efficiency (R), while the techno-economic approach incorporated multiple objectives. The comparative analysis demonstrated that the techno-economic optimization method outperformed the conventional method. This study emphasizes the significance of considering multiple objectives and integrating techno-economic factors in optimizing clay adsorption processes. The successful application of the techno-economic optimization approach highlights its potential as a robust optimization method, particularly in the field of wastewater treatment. The findings provide valuable insights for optimizing adsorption and advancing environmental remediation practices.

Preparation of Lignin-Based Nanoparticles with Excellent Acidic Tolerance as Stabilizer for Pickering Emulsion.

In this work, novel lignin-based nanoparticles (LβNPs) with high acidic tolerance were successfully prepared via electrostatic interaction between β-alanine and lignin nanoparticles. The effects of the mass ratio of lignin nanoparticles to β-alanine and pH value on the morphology and particle sizes of LβNPs were investigated with the aim of obtaining the ideal nanoparticles. The optimized LβNPs were spherical in shape with an average particle size of 41.1 ± 14.5 nm and exhibited outstanding structure stability under high acidic conditions (pH < 4). Subsequently, Pickering emulsions stabilized by LβNPs were prepared using olive oil as the oil phase. Additionally, the effects of pH value, droplet size, morphology, and storage stability on Pickering emulsions were also analyzed. The emulsions displayed excellent stability, and were stable against strongly acidic conditions (pH < 4) after 30 days of storage. The study presented a promising approach to preparing lignin-based nanoparticles with high acidic tolerance (an ideal type of stabilizer to prepare emulsions), and exhibited extremely high potential application values in the fields of drug delivery, food additives, and oily wastewater treatment.

Preparation and characterization of quaternary bacterial cellulose composites for antimicrobial oil‐absorbing materials

AbstractThe treatment of various types of oily wastewater is paramount for environmental protection. Bacterial cellulose (BC) stands out as a highly promising material for oil/water separation, owing to its exceptional mechanical properties and three‐dimensional porous structures. However, excessive hydroxyl groups on BC make it highly hydrophilic, reducing oil absorption and promoting bacterial growth, affecting its stability. To address these challenges, we developed a straightforward in situ polymerization method for the preparation of BC‐DMC composites. The innovation lies in the concurrent enhancement of BC's hydrophobicity and antimicrobial properties only through the addition of 2‐(Methacryloyloxy)ethyltrimethylammonium chloride (DMC), considerably simplifying the synthesis of materials possessing oil‐absorbing and antimicrobial properties. Morphological and structural characterization results confirmed the successful combination of DMC onto BC while maintaining its porous structure. After process parameter optimization, the BC‐DMC composites exhibited a remarkable increase in contact angle (117.7° compared with pure BC's 19.5°). It also demonstrated excellent oil absorption performance, with maximum capacities exceeding 30 g/g for different oils, maintaining values above 20 g/g even after eight cycles. In addition, the BC‐DMC composites exhibited strong antibacterial activity, with rates of 82.4% against Escherichia coli and 97.5% against Staphylococcus aureus. The antibacterial mechanism of the BC‐DMC composites was also discussed. Our novel BC‐DMC composites provides excellent oil absorption and antibacterial properties, making it highly applicable in the field of oily wastewater treatment and serving as a valuable reference for other researchers.

Pretreatment of 3-hydroxyacetophenone in pharmaceutical wastewater using combined salting-out crystallization+ Fenton system and subsequent impact analysis of effluent water

ABSTRACTSelecting a suitable pretreatment process for pharmaceutical wastewater that is difficult to treat biochemically so that it can enter the subsequent biochemical treatment. In this study, pharmaceutical wastewater consisting of 45 g/L sodium bisulfate, 9 g/L 3-hydroxyacetophenone (3-HAP), and 36.75 g/L sulfuric acids,which is a kind of typical pharmaceutical wastewater, was used for the pretreatment case study, and the process was screened by technology. A salting-out crystallization+Fenton system(SC-F) was developed for the treatment of this wastewater. The salting-out agent is formed by the pH adjustment process without additional additions and the salting-out crystallization effect is significant for the precipitation of 3-HAP from the wastewater. Subsequently, the optimal operating conditions for SC-F were derived from experiments as H2O2 of 0.4692 mol/L, n(H2O2):n(Fe2+)=30:1, pH=3. Under optimal conditions, the reaction time of 2 h achieved a COD removal rate of 90% and a BOD/COD value of 0.56, confirming the effectiveness of the technology in treating this wastewater. Additionally, it was discovered that the Fenton treatment was not significantly impacted by the inorganic components of the effluent. Analysis of effluent properties and possible effects on subsequent treatment by LC-MS and toxicity analysis. The results show that the biodegradability are enhanced by the pretreatment technology. However, the effluent still suffers from high acidity and high salt content, and this study proposes a solution to this problem. Furthermore, research on the treatment of 3-HAP wastewater has not been reported and this study provides a new case study in the field of wastewater treatment.

Preparation and characterization of γ-AlOOH/Fe3O4 for the highly effective removal of Congo red from wastewater

Due to the highly toxic and non-degradable nature of Congo red (CR) in wastewater, how to effectively separate CR from an aqueous solution remains a major challenge in the field of wastewater treatment. Consequently, an γ-AlOOH/Fe3O4 composite was prepared using the sol-gel method under ultrasonic stirring conditions. The structural and surface properties of the magnetic γ-AlOOH/Fe3O4 composite were analyzed in detail using a range of physical and chemical characterization methods. It was shown that the γ-AlOOH/Fe3O4 composite possessed the advantages of its layered structure, high porosity, and positively charged surface, all of which were conducive to improving the adsorption capacity of CR. During our CR adsorption experiments, the maximum adsorption amount reached 1350.11 mg g−1. Simultaneously, the whole adsorption process was more consistent with the pseudo-second order kinetic and Langmuir isotherm model. The adsorption activation energy and thermodynamic data prove that the adsorption process was chemisorption, spontaneous, and endothermic. In addition, the γ-AlOOH/Fe3O4 composite can be easily separated from treated-wastewater upon the application of an external magnetic field and its excellent reproducibility increases its practical application value. Therefore, the γ-AlOOH/Fe3O4 composite synthesized in this study has a wide range of practical applications.

Facile Synthesis of Ce-MOF for the Removal of Phosphate, Fluoride, and Arsenic

Ce-MOF was synthesized by a solvothermal synthesis method and was used to simultaneously remove phosphate, fluoride and arsenic (V) from water by adsorption. Ce-MOF was characterized by a nitrogen adsorption–desorption isotherm, scanning electron microscopy, and infrared spectroscopy. The effects of initial concentration, adsorption time, adsorption temperature, pH value and adsorbent on the adsorption properties were investigated. A Langmuir isotherm model was used to fit the adsorption data, and the adsorption capacity of phosphate, fluoride, and arsenic (V) was calculated to be 41.2 mg·g−1, 101.8 mg·g−1 and 33.3 mg·g−1, respectively. Compared with the existing commercially available CeO2 and other MOFs, Ce-MOF has a much higher adsorption capacity. Furthermore, after two reuses, the performance of the adsorbent was almost unchanged, indicating it is a stable adsorbent and has good application potential in the field of wastewater treatment.

Visible light driven S-scheme GQDs/BiOBr heterojunction with enhanced photocatalytic degradation of Rhodamine B and mechanism insight

A crucial and desirable objective in the wastewater treatment field is to design photocatalysts that can efficiently remove emerging pollutants while also being environmental-friendly. This work proposed a novel graphene quantum dots/BiOBr (GQDs/BiOBr) heterojunction with strong interfacial interactions through a hydrothermal method. Consequently, in just 140 min, RhB was almost entirely photodegraded by the GQDs/BiOBr and a rate constant 3.26 times higher than pristine BiOBr. The enhanced photocatalytic activity of GQDs/BiOBr was primarily associated with strengthened visible light absorption and improved charge transfer efficiency, as demonstrated through both experimental characterizations and density functional theory (DFT) calculation. Furthermore, with only a minor alteration in the surface chemical structure, GQDs/BiOBr retained strong photocatalytic ability after five cycles (RhB degradation of 85.17 %). The construction mechanism of S-scheme heterojunction, photogenerated carriers' transfer and photocatalytic mechanism were deduced by DFT calculation. The results derived from the radical trapping experiments as well as electron spin resonance (ESR) indicated that the presence of h+ and ·O2− were crucial for the degradation process of RhB. Finally, possible degradation intermediates had been identified and pathways of RhB were proposed, and the results of the toxicity assessment showed that ecotoxicity could be reduced or even eliminated. This effective and reliable visible-light-driven photocatalyst may be applied to build a photocatalytic degradation system for the environmentally friendly and energy-efficient removal of organic pollutants.

Identification of structural and optical properties and adsorption performance of (Cd0.4Ni0.4Mn0.2)Fe2-xRuxO4 nanoparticles for the removal of Congo red dye

In the field of industrial wastewater treatment, the application of highly efficient methods such as adsorption is crucial for effectively eliminating dangerous pollutants before effluent discharge. Ferrite nanoparticles (NPs) have emerged as promising candidates for the efficient and sustainable removal of dyes from wastewater. Therefore, the synthesis, characterization, and application of (Cd0.4Ni0.4Mn0.2)Fe2-xRuxO4 (0 ≤ x ≤ 0.04) NPs as adsorbents for the removal of Congo Red (CR) dye, is reported in this study. The X-ray powder diffraction (XRD) analysis has confirmed the purity of the samples with a very small amount of hematite phase. The prepared NPs have pseudo-spherical morphology and average particle size in the range of 12–17 nm. Furthermore, the elemental compositions, estimated from the energy dispersive x-ray (EDX) measurements, indicate the homogenous distribution of elements and the substitution of the Fe3+ host ions by the Ru3+ dopant. As the Ru content increases from 0.00 to 0.04, SBET increases from 52.39 to 78.34 m2/g, respectively. Furthermore, the pore diameter, ranging between 12.71 and 18.38 nm, reveals the mesoporous nature of the prepared samples. The direct and indirect bandgap energy, calculated from UV–vis spectroscopy analysis, is in the range of 3.049–3.232 eV and 1.894–2.642 eV, respectively. The adsorption performance of the prepared NPs for the removal of CR dye solution was investigated by varying the contact time, adsorbent amount, pH, and reaction temperature. The adsorption process follows a second-order kinetic model and the NPs with x = 0.015 revealed the highest adsorption rate with a rate constant k2 = 2.7 × 10−3 g.mg−1.min−1. The optimum experimental conditions, achieved in the presence of 80 mg of (Cd0.4Ni0.4Mn0.2)Fe1.985Ru0.015O4 NPs at 308 K and in the acidic medium at pH = 3.45, result in the removal of 87.5 % of CR dye after 60 min. After applying several non-linear adsorption isotherm models, mainly Langmuir, Freundlich, and Temkin isotherms, the experimental data were well-fitted with the Temkin isotherm model. The strong interactive force between CR and (Cd0.4Ni0.4Mn0.2)Fe1.985Ru0.015O4 nanoparticles is revealed from the high value of bT knowing that bT = 182.91 J.mol−1.

Adsorptive removal of heavy metals, dyes, and pharmaceuticals: Carbon-based nanomaterials in focus

The use of carbon-based nanomaterials, including carbon nanotubes, carbon dots, graphene/graphene oxide, fullerene, and their derivatives, in the removal of emerging pollutants from wastewater has become a promising method in water treatment. These nanomaterials exhibit exceptional adsorption capabilities and selectivity due to their extensive surface area, customizable surface chemistry, and unique structural features, which involve factors like π-π interactions, electrostatic interactions, and specific surface functional groups. A notable experiment demonstrated the effectiveness of carbon nanotubes as adsorbents for removing Ismate violet 2R dye from contaminated water. The results showed a remarkable maximum removal efficiency of 91.71 % at a concentration of 10 mg/L within a brief 120-min period. This article conducts a comprehensive evaluation of the adsorptive removal of emerging pollutants from wastewater using carbon-based nanomaterials, with a focus on developments between 2015 and 2023. An in-depth bibliometric analysis of 1285 research publications retrieved from the Web of Science (WOS) and Scopus databases reveals a substantial increase in the number of publications, rising from 50 in 2015 to 158 in 2023. This signifies a burgeoning emphasis on both practical application and technological advancement in this domain. Furthermore, this review explores the intricacies of adsorption mechanisms, factors influencing the adsorption performance of carbon-based nanomaterials, and the associated challenges and limitations when applied in wastewater treatment. By thoroughly investigating these constraints and potential advantages, this article provides valuable insights for the development of future carbon-based nanomaterials, aiming to enhance their efficiency and expand their applications in the field of wastewater treatment.

Toward Climate Neutrality: A Comprehensive Overview of Sustainable Operations Management, Optimization, and Wastewater Treatment Methods

Various studies have been conducted in the fields of sustainable operations management (SOM), optimization, and wastewater treatment, yielding unsubstantiated recovery. In the context of Europe’s climate neutrality vision, this paper reviews effective decarbonization strategies and proposes sustainable approaches to mitigate carbonization in various sectors such as buildings, energy, industry, and transportation and how these interlink with wastewater management. The study also explores the role of digitalization in decarbonization and reviews policies that can direct governments’ actions towards a climate-neutral society. This paper presents a review of optimization approaches applied in the fields of science and technology, incorporating modern optimization techniques based on various peer-reviewed published research papers. It emphasizes non-conventional energy and distributed power-generating systems along with the deregulated and regulated environment. Additionally, this paper critically reviews the performance and capability of the micellar-enhanced ultrafiltration (MEUF) process in the treatment of dye wastewater. The review presents evidence of the simultaneous removal of co-existing pollutants and explores the feasibility and efficiency of biosurfactants instead of chemical surfactants. Lastly, the paper proposes a novel Firm–Regulator–Consumer-Technology Enablers/Facilitators interaction framework to study operations, decisions and interactive cooperation considering the relationships between the four agents through a comprehensive literature review of SOM. The proposed framework provides support for exploring future research opportunities and holistic sustainability initiatives.

Preparation of a Novel Ag/CFOOVs Composite Catalyst and Efficient Degradation of Phenol in a H2O2-based Fenton-like System

Although CuFe2O4 has been widely used in the field of Fenton-like wastewater treatment, its ability to activate H2O2 still needs to be further improved. In this context, a novel Agx/CFOOVs (x represents the theoretical mass percentage of Ag) composite catalyst was prepared by the tartaric acid reduction method for the first time, and its degradation performance and degradation mechanism of Phenol in a H2O2-based Fenton-like system were investigated. Through a series of characterizations, the successful preparation of the catalyst was confirmed. The degradation experiment showed that the degradation rate of 50mg/L Phenol by Ag2/CFOOVs/H2O2 system was 98.55% within 15min, which was a significant improvement in the degradation efficiency compared with that of CuFe2O4 and CFOOVs. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) confirmed the successful introduction of oxygen vacancies (OVs). Electrochemical impedance spectroscopy (EIS) showed that Ag2/CFOOVs had the lowest impedance, and the synergistic effect of OVs and Ag effectively enhanced the degradation capability of the catalysts for Phenol. The capture experiments of active species and ESR tests showed that the main active species of the Ag2/CFOOVs/H2O2 system were 1O2 and •OH. This study provides a new reference for the introduction of OVs and Ag in Fenton-like catalysts and their application to wastewater treatment.

Advance in the sulfur-based electron donor autotrophic denitrification for nitrate nitrogen removal from wastewater.

In the field of wastewater treatment, nitrate nitrogen (NO3--N) is one of the significant contaminants of concern. Sulfur autotrophic denitrification technology, which uses a variety of sulfur-based electron donors to reduce NO3--N to nitrogen (N2) through sulfur autotrophic denitrification bacteria, has emerged as a novel nitrogen removal technology to replace heterotrophic denitrification in the field of wastewater treatment due to its low cost, environmental friendliness, and high nitrogen removal efficiency. This paper reviews the advance of reduced sulfur compounds (such as elemental sulfur, sulfide, and thiosulfate) and iron sulfides (such as ferrous sulfide, pyrrhotite, and pyrite) electron donors for treating NO3--N in wastewater by sulfur autotrophic denitrification technology, including the dominant bacteria types and the sulfur autotrophic denitrification process based on various electron donors are introduced in detail, and their operating costs, nitrogen removal performance and impacts on the ecological environment are analyzed and compared. Moreover, the engineering applications of sulfur-based electron donor autotrophic denitrification technology were comprehensively summarized. According to the literature review, the focus of future industry research were discussed from several aspects as well, which would provide ideas for the application and optimization of the sulfur autotrophic denitrification process for deep and efficient removal of NO3--N in wastewater.

Myrica esculenta Leaf Extract-Assisted Green Synthesis of Porous Magnetic Chitosan Composites for Fast Removal of Cd (II) from Water: Kinetics and Thermodynamics of Adsorption.

Heavy metal contamination in water resources is a major issue worldwide. Metals released into the environment endanger human health, owing to their persistence and absorption into the food chain. Cadmium is a highly toxic heavy metal, which causes severe health hazards in human beings as well as in animals. To overcome the issue, current research focused on cadmium ion removal from the polluted water by using porous magnetic chitosan composite produced from Kaphal (Myrica esculenta) leaves. The synthesized composite was characterized by BET, XRD, FT-IR, FE-SEM with EDX, and VSM to understand the structural, textural, surface functional, morphological-compositional, and magnetic properties, respectively, that contributed to the adsorption of Cd. The maximum Cd adsorption capacities observed for the Fe3O4 nanoparticles (MNPs) and porous magnetic chitosan (MCS) composite were 290 mg/g and 426 mg/g, respectively. Both the adsorption processes followed second-order kinetics. Batch adsorption studies were carried out to understand the optimum conditions for the fast adsorption process. Both the adsorbents could be regenerated for up to seven cycles without appreciable loss in adsorption capacity. The porous magnetic chitosan composite showed improved adsorption compared to MNPs. The mechanism for cadmium ion adsorption by MNPs and MCS has been postulated. Magnetic-modified chitosan-based composites that exhibit high adsorption efficiency, regeneration, and easy separation from a solution have broad development prospects in various industrial sewage and wastewater treatment fields.

Application of chitosan-based materials in wastewater treatment

Chitosan, as a natural polysaccharide material, plays a great role in the field of wastewater treatment due to its good biodegradability, antimicrobial activity, and other properties. However, it may have some differences in the processes of adsorption, flocculation, and membrane separation. We comprehensively describe the application effect and mechanism of action of chitosan-based materials on the above three major water treatment processes. In the adsorption process, chitosan-based adsorbents such as hydrogels and chitosan beads are prepared by cross-linking, impregnation, and the introduction of functional groups. These chitosan-based materials exerted efficient removal performance in the adsorption of heavy metals, organic dyes, anionic pollutants, etc., which was attributed to their large specific surface area and abundant functional groups. In the flocculation process, the chitosan-based materials were modified by grafting and modifying their shape, while heavy metal ions, organic dyes, and algae were removed using processes such as chelation and charge neutralization. In the membrane separation process, a number of nanofiltration and microfiltration membranes were created by coating chitosan ions, and physicochemical modification was done for the separation of heavy metal ions and emulsified oil droplets in water to improve the fouling resistance and retention rate of the membrane materials. This paper reviews the application of chitosan-based materials in wastewater treatment and proposes that in-depth studies on their toxicity and reusability should be conducted in the future, with a view to playing a role in areas such as the removal of malodorous water odors.

Study and Application Status of Ultrasound in Organic Wastewater Treatment

Ultrasound waves have been widely used in the field of organic wastewater treatment due to their mechanical, thermal, and chemical effects derived from their cavitation effect. Many researchers have combined ultrasound waves with other organic wastewater treatment methods because they have the potential to offset the disadvantages of other methods. In recent years, many authors within the literature have reviewed the application of ultrasound combined with a certain wastewater treatment method. In this review, we introduce the working mechanism of ultrasound in the treatment of organic wastewater and then examine the synergistic effects of ultrasound with other organic wastewater treatment methods based on various applications, indicating a strong synergistic effect between ultrasound and other wastewater treatment methods. Subsequently, we introduce typical ultrasound-enhanced organic wastewater treatment equipment and propose some possible developmental directions for ultrasound in the treatment of organic wastewater.

A machine learning approach for the estimation of photocatalytic activity of ALD ZnO thin films on fabric substrates

Research in the field of photocatalytic wastewater treatment is striving to enhance catalyst materials to achieve high-performance systems. A promising approach to this goal has been immobilizing photocatalytic materials on fibrous substrates via atomic layer deposition (ALD). Nevertheless, both the ALD process and the assessment of photocatalytic performance involve a multitude of parameters necessitating thorough investigation. In this study, we employ popular machine-learning algorithms, including Support Vector Regression (SVR) and Artificial Neural Networks (ANN), to predict the photocatalytic activity of ALD-coated textiles. The photocatalytic activity is evaluated through methylene blue and methyl orange degradation tests. Machine learning algorithms are tested and trained using the k-fold cross-validation technique. The findings demonstrate that the ANN and SVR methods utilized in this research can predict catalytic activity with mean absolute percentage errors (MAPE) of 2.35 and 3.25, respectively. This study illuminates that, within the defined range of process parameters, the photocatalytic activity of ALD-coated textiles can be precisely estimated with suitable machine-learning algorithms.