Application In Wastewater Treatment Research Articles

Transient MHD Darcy-Forchheimer of Williamson-Casson flow with CCS: Application of wastewater treatment

With regards to the Cattaneo-Christoph (CCS) speculation, the thermal and mass transfer of a MHD Williamson-Casson ferrofluid flow through a permeable medium obeying the Darcy-Forchmeier law through an extended chamber or slab is carefully considered. The chemical reaction and Buongiorno nanofluid model were modified in the model to describe the nanoscale properties of liquid particles. Heat sources can be divided into two categories: linear and exponential space-dependent convection heat sources. The entire governing equations are changed to common differential terms, using a reasonable similarity change. These equations and their associated boundary conditions are calculated numerically via the fourth-order Runge-Kutta method. Comparison was made with the analytical solution in a special case, and very good agreement was reached. Economic success with deeper water purification can be attained by developing models for wastewater treatment facilities, conducting experiments and calculations on them, and making predictions for their nature in order to improve their cleaning efficiency, Prevent issues from arising during construction, operation, and reconstruction. The structural parameters of the quencher were physically modeled using mathematical modeling; It is possible to establish a cost-effective and effective filter model for industry and small settlements using the calculations and vertical filter model created in the article. Furthermore, it will be feasible to produce. Our mathematical procedure assure that: the deposit’s mass will be diminished through treated water under attractive field impacts; The magnetic field openness with nanometer-sized particles modifies the physical and synthetic properties of water particles bringing about exceptional characteristics; the water concentration will be decreased with the increase in the bending modulus; This means that in wastewater treatment the sediment mass will decrease.

Efficient Rhodamine B removal by photocatalysis using polyacrylonitrile/Ag2S nanofibers prepared by combining electrospinning technology and facile gas–solid reaction

AbstractPAN/Ag2S nanofibers prepared by combining conventional electrospinning technology and facile gas–solid reaction were used to activate peroxymonosulfate for Rhodamine B (RhB) degradation by photocatalysis using visible light. The material properties were analyzed by UV–Vis–NIR, XRD, SEM, FTIR, EIS, and BET techniques. The results indicated that Ag2S nanoparticles with a size of ≈10–20 nm were homogeneously attached to the nanofiber surface. The PAN/Ag2S can remove 96.98% RhB (5 mg L−1) after 120 min at pH 7. Through the identification of reactive oxygen species (ROSs) and the calculation of band gap and band potentials, the photocatalytic mechanism was proposed. Results from the identification of ROSs demonstrate that the contribution of the ROSs was in the order of h+ > 1O2 ≈ O2•− ≈ SO4•− > HO• in which h+ has an important role in RhB degradation. The as‐prepared PAN/Ag2S nanofibers with high photocatalytic activity, effective working under visible light, high flexibility, and easy recovery from the aqueous phase, have the potential for practical applications in wastewater treatment.

Novel MXene/PVDF nanocomposite ultrafiltration membranes for optimized Eriochrome black T (azo dye) removal

In the context of recycling and reusing textile wastewater, the quest for a membrane possessing superior efficiency has garnered considerable attention. This research endeavors to advance this objective by introducing a novel asymmetric ultrafiltration membrane constructed from PVDF (Polyvinylidene Fluoride) modified with MXene through bulk modification, thereby augmenting its resistance to fouling for textile wastewater treatment applications. The investigation employed a comprehensive array of characterization techniques. The proposed interaction mechanism between the contents of PVDF/MXene and the interaction mechanism of composite membrane with water molecules were also presented. Comparative analysis with pure membranes revealed that the incorporation of MXene resulted in enhanced hydrophilicity and porosity, concurrently reducing its surface roughness when compared to a pristine membrane. The lowest water contact angle about 38.5 (⁰) was observed in the mixed matrix membrane containing 0.5 wt% MXene. The developed membranes exhibited a maximum pure water flux of 538 LMH and a flux of 467.8 LMH for EBT dye solution. Furthermore, optimization of the nanocomposite membrane composition led to nearly complete rejection of Eriochrome black T (EBT). A continuous improvement in the flux recovery ratio (FRR%) culminating in a peak value of 85.6% for the MMMs prepared from 0.5 wt% MXene.

Potential Nanoparticles to Integrate with Ceramic Membranes for Treating Industrial Wastewater: A Review

Due to human indifference and reckless oily wastewater production from industry, environmental or ecological pollution has become a challenge for our planet. Oily industrial wastewater mostly released by oil fields, refineries, cars, palm oil sectors, and many others is one of the biggest dangers. Oil and water can be virtually completely separated using membrane-based technologies. However, these technologies still face challenges in upholding efficiency over extended periods due to membrane fouling induced by oil droplets mixing with the membranes. Therefore, to overcome these challenges, the creation of polymeric, ceramic, and metallic-based membrane materials with enhanced performance is the focus of research in this field. In this review, various published approaches applied for treating industrial wastewater by using Ceramic Membranes integrated with nanoparticles were focused initially. Then, a modified experimental procedure from the literature for wastewater treatment process by using ceramic membranes is discussed. The majority of studies indicate nearly total oil rejection and increased outputs. Silicon carbide (SiC), Titanium dioxide (TiO2), Aluminum Oxide (Al2O3), Iron Oxide (Fe2O3) Powdered Activated Carbon (PAC), Zirconium dioxide (ZrO2), Alumina powder (Al), Silica (SiO2), Graphene Oxide (GO), and Silver (Ag) are identified potential nanoparticles to mix with ceramic membranes for wastewater treatment application.

Efficient removal of methylene blue and methyl red dyes using a novel adsorbent derived from Saponaria officinalis Root via H3PO4, H2SO4, and KOH-activation: Optimization, kinetics, and isotherm study

This study focuses on the optimization, kinetics, and isotherms of a novel adsorbent derived from Saponaria officinalis root for efficient removal of methylene blue and methyl red dyes. The preparation of the activated carbon involved specific parameters such as activating agents, impregnation time, and activation temperature. Results indicated a robust adsorption capacity, with the Langmuir isotherm model fitting well to the experimental data. The pseudo-second-order kinetic model demonstrated high applicability, highlighting the potential of the developed adsorbent for wastewater treatment applications. The adsorbent exhibited impressive iodine adsorption capacities ranging from 336.42 to 1250.09 mg/g, with efficient removal rates of over 95% for methylene blue and 75% for methyl red dyes within specific time frames.

Immobilized microalgae: principles, processes and its applications in wastewater treatment.

Microalgae have emerged as potential candidates for biomass production and pollutant removal. However, expensive biomass harvesting, insufficient biomass productivity, and low energy intensity limit the large-scale production of microalgae. To break through these bottlenecks, a novel technology of immobilized microalgae culture coupled with wastewater treatment has received increasing attention in recent years. In this review, the characteristics of two immobilized microalgae culture technologies are first presented and then their mechanisms are discussed in terms of biofilm formation theories, including thermodynamic theory, Derjaguin-Landau-Verwei-Overbeek theory (DLVO) and its extended theory (xDLVO), as well as ionic cross-linking mechanisms in the process of microalgae encapsulated in alginate. The main factors (algal strains, carriers, and culture conditions) affecting the growth of microalgae are also discussed. It is also summarized that immobilized microalgae show considerable potential for nitrogen and phosphorus removal, heavy metal removal, pesticide and antibiotic removal in wastewater treatment. The role of bacteria in the cultivation of microalgae by immobilization techniques and their application in wastewater treatment are clarified. This is economically feasible and technically superior. The problems and challenges faced by immobilized microalgae are finally presented.

New insight on the influence of surface-modified clay cup with stirring effect for bioelectricity production by utilizing septic tank wastewater

The removal of organic particulates from septic tank waste waters is the most crucial part of biological treatment processes. In this regard, the present study explores the potential applications of septic tank waste water treatment (STWW) system in the removal of organic matter and energy generation using Microbial fuel cells. The effect of acrylic varnish coating over the clay cup along with stirring (ACS- SMFC) has produced 70% more electricity than the uncoated clay cups without stirring, with the OCV of 984 ± 2 mV, current and power density of 706 ± 5.78 mA/m3 and 61.17 ± 0.29 mW/m3. The fabrication of the clay cup proves the presence of Niobium and chlorine functional groups in EDAX analysis, which affirms its high electron flow and superconductivity for better electricity production. SEM and confocal laser scanning microscopy affirmed the catabolic conversion of organic substrates of STWW through microbial communities of biofilm on bioelectricity production. Thus the higher COD removal value of 60.3 ± 0.09% was achieved in the ACS –SMFC module by utilizing STWW as substrate. Acrylic varnishing's efficacy on clay cups was confirmed via Fourier transform infrared spectroscopy with prominent peaks between 700 cm−1 to 3612 cm−1.

A customized 3D bio-macroporous cryogels for efficient and selective gold extraction

The swift and efficient extraction of gold from electronic wastes carries significant economic and environmental benefits. In the present work, chitosan and keratin were modified with vinyl pyrrolidone via grafting cryopolymerization used UV-irradiation for efficient Au(III) removal from actual electronic waste solution. The rapidly attaining adsorption equilibrium for Au(III) within just 4 h can be attributed to the biosorbent macroporous nature. Under ideal conditions (C0 = 1200 mg g−1, 308 K and pH 3), the Freundlich model exhibited superior fitting, showcasing the biosorbent's remarkable adsorption capacity for Au(III) at an impressive amount of 613.27 mg g−1. An Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES, Varian) was implemented to measure the adsorption of Au(III) and other coexisting ions. Additionally, the biosorbent displayed enhanced thermal stability and a prolonged shelf-life, indicating its potential for use in challenging environmental conditions. In addition to its stability, the material maintained its Au(III) adsorption efficiency after four consecutive usage cycles. In addition, it exhibited the capacity to specifically adsorb Au(III) from leaching solutions of electronic waste, resulting in a recovery rate of 89.2 %. The presence of amino (–NH2) and sulfide (-S-S-) functional groups on the biosorbent played a pivotal role in capturing Au(III) ions through electrostatic and chelation mechanisms. The presence of sulfide linkage and amino (–NH2) functionality, a major component of keratin is a pristine factor in this study, particularly well-suited for Au(III) extraction. The crosslinked biosorbent introduced random pores due to its random cooling process, enabling efficient diffusion and more significant Au(III) retention than traditional gels. In addition to its capacity for recovering precious metals from electronic waste, this biosorbent is a cost-effective solution with promising applications in environmental remediation and wastewater treatment.

Effect of suspended solids from anaerobic digested wastewater on performance and microbial community of autotrophic nitrogen removal process

Most anaerobically digested wastewaters have high concentrations of suspended solids, while little is known about whether they adversely affect the performance of the autotrophic nitrogen removal process. In this work, using air-lift internal circulation reactor we studied the effect of suspended solids on the autotrophic nitrogen removal process by adding 600–900 mg/L suspended solids from digested swine wastewater to the influent (R–SS). The results showed that during the formation of autotrophic nitrogen removal granular sludge, suspended solids containing Ca, Mg, Cu P, and Pb can enter the granular sludge, occupy the ecological niche of anammox bacteria, lead to loose internal structure, and damage the internal anoxic environment. It then reduces the settling performance in the R–SS, causes heavy wash-out of granular sludge from the R–SS reactor (2.5 times more than the control, R–CK), and finally reduces the maximum nitrogen removal rate of the autotrophic nitrogen removal process from 5.16 kg N/m3/d to 4.31 kg N/m3/d. Meanwhile, the metagenomic analysis showed that suspended solids reduce the relative abundance of reads from key nitrogen genes of anammox bacteria yet increases reads from both nitrite-oxidizing and denitrifying bacteria, especially nir and nor genes. Further analysis of 16 highly abundant genomes assembled via metagenomics showed that suspended solids decrease the relative abundance of Kuenenia_seed103, an anammox bacterium, from 13.36% (R–CK) to 11.03% (R–SS). Since suspended solids can act as a carbon source for denitrifiers to compete with nitrite or nitric oxide with anammox bacteria, the denitrifier community has progressed from a simple denitrifier consisting of only one or two denitrification steps (nar or nos) that acts as an ammonia and nitrite sink to a complete one that directly reduces nitrite to nitrogen gas. This study will lay a good foundation for its application in wastewater treatment.

Novel cow dung-doped sludge biochar as an efficient ozone catalyst: Synergy between graphitic structure and defects induces free radical pathways

A composite material, cow dung-doped sludge biochar (Zn@SBC-CD), was synthesized by one-step pyrolysis using ZnCl2 as an activating agent and applied to a catalytic ozonation process (COP) for methylene blue (MB) removal. SEM, XRD, FTIR, XPS and BET analyses were performed to characterize the biochar (BC) catalysts. Zn@SBC-CD had high graphitization degree, abundant active sites and uniform distribution of Zn on its surface. Complete removal of MB was achieved within 10 min, with a removal rate much higher than that of ozone alone (32.4%), implying the excellent ozone activation performance of Zn@SBC-CD. The influence of experimental parameters on MB removal efficiency was examined. Under the optimum conditions in terms of ozone dose 0.04 mg/mL, catalyst dose 400 mg/L and pH 6.0, COD was completely removed after 20 min. Electron paramagnetic resonance (EPR) analysis revealed radical and non-radical pathways were involved in MB degradation. The Zn@SBC-CD/O3 system generated superoxide anion radicals (•O2−), which were the main active species for MB removal, through adsorption, transformation, and transfer, Furthermore, Zn@SBC-CD exhibited good reusability and stability in cycling experiments. This study provides a novel approach for the utilization of cow dung and sludge in synthesis of functional biocatalysts and application in organic wastewater treatment.

Interspecies cooperation-driven photogenerated electron transfer processes and efficient multi-pathway nitrogen removal in the g-C3N4-anammox consortia biohybrid system

Photocatalytic materials-microbial biohybrid systems pave the way for solar-driven wastewater nitrogen removal. In this study, interspecies cooperation in photogenerated electron transfer and efficient nitrogen removal mechanism in the g-C3N4-anammox consortia biohybrid system were first deciphered. The results indicated that the essential extracellular electron carriers (cytochrome c and flavin) for anammox genomes were provided by associated bacteria (BACT3 and CHLO2). This cooperation, regulated by the ArcAB system and electron transfer flavoprotein, made anammox bacteria the primary photogenerated electron sink. Furthermore, an efficient photogenerated electron harness was used to construct a reductive glycine pathway (rGlyP) in anammox bacteria inventively, which coexisted with the Wood–Ljungdahl pathway (WLP), constituting a dual-pathway carbon fixation model, rGlyP-WLP. Carbon fixation products efficiently contributed to the tricarboxylic acid cycle, while inhibiting electron diversion in anabolism. Photogenerated electrons were targeted channeled into nitrogen metabolism-available electron carriers, enhancing anammox and dissimilatory nitrate reduction to ammonium (DNRA) processes. Moreover, ammonia assimilation by the glycine cleavage system in rGlyP established an alternative ammonia removal route. Ultimately, multi-pathway nitrogen removal involving anammox, DNRA, and rGlyP achieved 100 % ammonia removal and 94.25 % total nitrogen removal efficiency. This study has expanded understanding of anammox metabolic diversity, enhancing its potential application in carbon-neutral wastewater treatment.

Silver doped anatase nanocomposite: a novel photocatalyst with advanced activity under visible light for waste-water treatment

Anatase is a universal semiconductor photocatalyst; however, its wide band-gap energy limits its entire solar spectrum absorption to only 5%. Anatase could be activated in the visible region via nobel metal deposition. This study reports on the facile synthesis of colloidal mono-dispersed anatase nanoparticles of 5 nm particle size via hydrothermal synthesis. Nobel metals (Silver, Nickel) were deposited on colloidal anatase surface. The photocatalytic activities of Ag–TiO2, and Ni–TiO2 were investigated for the degradation of basic fuchsin dye. Ag–TiO2 nanocomposite demonstrated enhanced adsorption activity in dark, as well as superior photocatalytic. Ag–TiO2 nanocomposite demonstrated enhanced removal efficiency by 70.8% under visible irradiation to virgin anatase. Ag–TiO2 nanocomposite demonstrated enhanced oxygen-lattice with low binding energy using XPS analysis. Ag–TiO2 experienced band gap energy of 2.35 eV compared with 3.2 eV for virgin anatase; this feature could secure enhanced solar absorption. Ag–TiO2 demonstrated excellent photo-degradation efficiency of 88% with 0.3% H2O2 under visible light. Deposited silver could catalyze H2O2 decomposition and could promote free radical generation; Ag–TiO2 nanocomposite is a promising photocatalyst for wastewater treatment applications.

Optimization of newly isolated Bacillus cereus α-amylase production using orange peels and crab shells and application in wastewater treatment.

A newly isolated amylolytic strain was identified as Bacillus cereus spH1 based on 16S and 16-23S gene sequencing (Accession numbers OP811441.1 and OP819558, respectively), optimization strategies, using one variable at time (OVAT) and Plackett-Burman design, were employed to improve the alpha-amylase (α-amylase) production. Condition inferred revealed that the optimal physical parameters for maximum enzyme production were 30°C, pH 7.5, and 12h of incubation, using tryptone, malt extract, orange (Citrus sinensis) peels, crab (Portunus segnis) shells, calcium, and sodium chloride (NaCl) as culture medium. The full factorial design (FFD) model was observed to possess a predicted R2 and adjusted R2 values of 0.9788 and 0.9862, respectively, and it can effectively predict the response variables (p = 0). Following such efforts, α-amylase activity was increased 141.6-folds, ranging from 0.06 to 8.5 U/mL. The ideal temperature and pH for the crude enzyme activity were 65°C and 7.5, respectively. The enzyme exhibited significant stability, with residual activity over 90% at 55°C. The maltose was the only product generated during the starch hydrolysis. Moreover, the Bacillus cereus spH1 strain and its α-amylase were used in the treatment of effluents from the pasta industry. Germination index percentages of 143% and 139% were achieved when using the treated effluent with α-amylase and the strain, respectively. This work proposes the valorization of agro-industrial residues to improve enzyme production and to develop a green and sustainable approach that holds great promise for environmental and economic challenges.

Peroxidase like activity of Prussian blue nanoparticles and visible light mediated catalytic degradation of methylene blue dye

The environmental impact of dyes, particularly those utilized in the pharmaceutical and textile industries, has been a growing concern due to their persistence and potential harm to ecosystems. Methylene Blue (MB) dye is one of the commonly used synthetic dyes known for its adverse effects on the environment. Thus a promising catalyst is required for the effective degradation of MB dye. To effectively degrade MB, we have synthesized Prussian blue nanoparticles (PBNPs) in this work using the co-precipitation technique. These nanoparticles showed the peroxidase like behavior by degrading hydrogen peroxide and generating ROS (reactive oxygen species) under visible light exposure, which oxidized MB leads to its degradation. This degradation process was investigated under various experimental conditions, including pH, catalyst dosage, and peroxide concentration. The results demonstrated that PBNPs exhibited remarkable catalytic activity and completely degrade the MB within 50 min under visible light. The degradation efficiency was found to be pH-dependent and optimum efficiency was found in pH range from 5 to 7. The kinetic studies were shown that this MB degradation process follows the first order kinetic models with the rate constant value 0.038 s−1, suggesting that the degradation process follows Fenton mechanism. The recyclability and stability of the PBNPs as a catalyst were also assessed, which showed that it can be used up to four cycles, demonstrating their potential for practical applications in dye wastewater treatment.

Mesoporous silica-grafted deep eutectic solvent-based mixed matrix membranes for wastewater treatment: Synthesis and emerging pollutant removal performance

Abstract Nano-enhanced membrane technology and deep eutectic solvents (DESs) have demonstrated effectiveness in addressing emerging environmental pollutants. This research centers on purifying water by removing heavy metals employing membranes enhanced with mesoporous silica and DES. Various DESs, including hexanoic acid, octanoic acid, and decanoic acid, were synthesized using tetrabutylammonium bromide (TBABr) as a base. The study combined a polysulfone-based membrane with mesoporous silica, aiming for efficient indigenous crafting to remove heavy metals. Mesoporous silica was blended with the synthesized DES solution, creating diverse membranes for heavy metal separation. The study characterized these membranes using various techniques such as scanning electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and contact angle measurements. Surface mapping confirmed the integration of silicon-based DES, reducing the membrane surface roughness from 4 to 1.4 nm. By adjusting the carboxylic acid chain length with TBABr and adding mesoporous silica, leaching ratios were reduced from 4.2 to 2.3%. Silica-grafted DES-based membranes exhibited a progressive increase in flux from 2.6 to 26.67 L/m2 h. The synthesized silicon-based membranes demonstrated outstanding performance, achieving rejection rates exceeding 80% for chromium and arsenic, maintaining an impressive 90% flux recovery ratio even at high flux rates. This study will envision the potential of nano-enhanced membrane technology utilizing DES for sustainable water purification and wastewater treatment applications to achieve the sustainable development goal (SDG) of clean water and sanitation (SDG-6).

Visible light-driven efficient degradation of Rhodamine B using rGO/Bi2O2CO3/BiOCl composite photocatalysts

In this study, rGO/Bi2O2CO3/BiOCl composite photocatalysts were prepared using a one-step solvothermal method. The formation and morphology of these photocatalysts were characterized through XRD, Raman, XPS, SEM, TEM, and other techniques. The efficiency of the composite photocatalysts was assessed by decreasing RhB under visible light. Among them, the photocatalytic activity of 4 wt% rGO/Bi2O2CO3/BiOCl was discovered to be the best, with a degradation rate as high as 96 % within 60 min. This is because the inclusion of rGO not only increased the specific surface area of the ternary materials, but also acted as a carrier for electrons transfer. Besides, the heterojunction structure constituted between Bi2O2CO3 and BiOCl also opens up a new pathway for carrier separation. Finally, we explored the degradation mechanism of rGO/Bi2O2CO3/BiOCl ternary materials in detail. This study holds an important reference for the synthesis of bismuth-based composite photocatalysts and has potential applications in wastewater treatment.

Enhancing photocatalytic performance of Cu6Fe2SnS8 by N doping using magnetic grinding method

Nitrogen doped quaternary metal sulfide Cu6Fe2SnS8 (CFTS) was prepared by magnetic grinding. The mechanochemical method has the advantage of simple synthesis of non-metallic doped polymetallic sulfides, and there is no solvent involved in the reaction process, which is very environmentally friendly. Non metallic doping can form electron capture centers on semiconductors, suppress the recombination of photo generated electron hole pairs, and extend electron lifetime. Moreover, doping N element into the CFTS lattice will lead to the formation of new energy states, thereby narrowing the energy band gap. The characterizations of XPS and EDS have proven the successful doping of N element into CFTS. In addition, the photocatalytic mechanism and the stability of the N-doped CFTS (N-CFTS) were studied through active substance capture experiments and cyclic experiments. The experimental results indicate that ·O2− is the main active substance in the degradation of MB by N-CFTS. After multiple cyclic experiment, the N-CFTS catalytic material still exhibits good crystal structure and photocatalytic stability. This photocatalytic material has great potential for applications in wastewater treatment and environmental remediation.

Deep eutectic solvent as an effective tool for enhanced photocatalytic activity of Cu2S@MoS2 nano-assemblies: A green approach

The scientific world has witnessed the emergence of plethora of green strategies to ameliorate the efficiency of nano-photocatalytic materials for waste water treatment applications. This work, for the first time, highlights the effect of ZnCl2 and urea-based DES on the morphology, electronic band structure and photocatalytic efficiency of Cu2S @MoS2 NPs compared to solvents like water, EDA and DETA. XRD and FT-IR analysis confirmed the formation of NPs and quite significant changes in the pattern of M-S bonds of Cu2S@MoS2 were observed upon variation of solvents. The FE-SEM analysis of NPs prepared in 1:1 composition of DES and water (Cu2S@MoS2 NPs - 1:1) showed entirely distinct nanoflower morphology compared to spherical arrangement shown by NPs prepared using other solvents. As a result, Cu2S@MoS2 NPs - 1:1 showed superior textural properties with a surface area of 89 m2/g in contrast to 7.4, 6.2 and 18 m2/g observed for NPs synthesized in water, EDA and DETA, respectively. Besides, wide band gap of 2.75 eV for Cu2S@MoS2 NPs - 1:1 induced favorable charge carrier recombination kinetics, which played an instrumental role in the degradation of tetracycline hydrochloride (TC) and rhodamine B (RB). Cu2S@MoS2 NPs - 1:1 showed best photocatalytic activity as 97% and 96% of TC and RB was removed after 90 min of visible light irradiation with no significant decline in removal efficiency till 5 cycles. Scavenger studies hinted towards the crucial role of h+ and ⋅ OH in degradation process and a mechanism was proposed accordingly. The superior photocatalytic activity of NPs prepared using DES compared to water and organic solvents showed that the inclusion of DES in synthesis schemes of NPs is an excellent strategy for improving their efficiency towards waste water treatment applications.

Construction of highly efficient carbon cloth-supported S-scheme Co3O4/AgIO4 heterojunction for photocatalytic degradation of Rhodamine B organic dye

The development of effective methods for the synthesis of supported photocatalysts instead of dispersive powdery photocatalysts has received great attention. Herein, a flexible visible-light-driven carbon cloth-supported Co3O4/AgIO4 composites was successfully prepared by combining electrodeposition and chemical coprecipitation method. After 40 min of visible-light illumination, 99.2 % of the rhodamine B can be degraded by carbon cloth-supported Co3O4/AgIO4 composites with electrodeposition duration of 50 min, showing a highest reaction rate constant of 10.5 × 10−2 min−1 which exceeds that of CC/Co3O4 and CC/AgIO4 by a factor of 58.39 and 2.67 times, respectively. The band structures of the samples were studied by valence band X-ray photoelectron spectroscopy, ultraviolet photoemission and theoretical calculations. The capture experiments confirmed that positive holes and the superoxide radicals are two main reactive species participating in the degradation of rhodamine B. The excellent photocatalytic reactivity can be attributed to the successful construction of S-scheme heterojunction between Co3O4 and AgIO4. The Co3O4/AgIO4 heterojunction not only inhibited the rapid recombination of charges but also reserved the oxidation and reduction ability of the holes in the valence band of AgIO4 and electrons in the conduction band of Co3O4. The work is of great significance in the development of carbon cloth-supported photocatalysts with good recyclability for practical applications of wastewater treatment.

Designing a self-breathing electrode modulated by spatial hydrophobic microenvironments with stabilized H2O2 generation for wastewater treatment

A novel self-breathing air-diffusion rod graphite electrode (ADE-RG) engineered with spatial hydrophobic microenvironments was developed to enhance H2O2 production without external air aeration. The microenvironments, created through thermal shaking-induced turbulence and centrifugal effect, significantly improved the air-diffusion capability. This innovation led to the increase in H2O2 generation (3.36 times higher than that in the unmodified system) due to a locally enhanced electric field, increased oxygen transfer rate, and improved selectivity for two-electron transfer process. Furthermore, incorporating polyepoxysuccinic acid into the electrolyte not only prevents electrode scaling but also minimizes H2O2 decomposition, culminating in the H2O2 concentration of 50.64 ± 2.92 mg L−1 cm−2. Notably, the system performed prominently in treating industrial rifampicin wastewater, achieving a degradation efficiency of 95.29 ± 0.47%, even under high-loading conditions (initial COD was 22,898.50 ± 405.17 mg L−1). These results indicate the significant potential of the self-breathing ADE-RG system in broad-scale wastewater treatment applications.