Purification Of Industrial Wastewater Research Articles

Band gap engineering of ADG/NiO nanocomposite and applications for photocatalytic reduction of nitrogen and photo-oxidation of dyes

The use of solar-driven semiconductor photocatalysis to solve energy and environmental issues is an intriguing and difficult subject. As a consequence, various types of photocatalysts have been developed subsequently to fulfill the requirements of photocatalysis.Since graphene was discovered, materials based on graphene have garnered considerable interest. The aloe-vera derived (ADG)/nickel oxide (NiO) nanocomposite is a notable example of a graphene derivative.The uniform structure of graphene fibre is altered by nickel oxide(NiO) which tunes its band gap and causes electronic arrangements within graphene that is requiste for photocatalysis. Herein, we have used a one-pot chemical approach to design aloe vera-derived graphene/nickel oxide nanocomposites (ADG/NiO), a novel photocatalyst that show high molar absorbance, suitable band gap of 2.68 eV, good photo-stability and reusability. Under solar light irradiation, the ADG/NiO nanocomposite exhibited remarkable photocatalytic activity. It effectively fixed nitrogen into ammonia with an apparent quantum efficiency(AQE) of 0.64% and efficiently photo-oxidized dyes. Specifically, it achieved a dye removal efficiency of 94.2% for methylene blue (MB) and 86.41% for Eosin-B, converting them into harmless inorganic species like CO2 and H2O within just 90 minutes. The cost-effective ADG/NiO nanocomposite shows significant potential as a photocatalyst activated by solar light for practical applications such as the selective generation of NH3 and the purification of industrial wastewater containing dyes.

ТЕРМОДИНАМИЧЕСКИЙ АНАЛИЗ ОКИСЛИТЕЛЬНО – ВОССТАНОВИТЕЛЬНЫХ РЕАКЦИЙ, ПРОТЕКАЮЩИХ ПРИ ГАЛЬВАНОКОАГУЛЯЦИОННОЙ ОЧИСТКЕ СТОКОВ

Abstract. One of the most important environmental problems is the purification of industrial wastewater from heavy metal ions. Various methods are used to solve this problem: chemical, physico-chemical, sorption, but the most promising method for cleaning industrial wastewater containing heavy metal ions, namely copper, nickel and zinc, is the galvanocoagulation method. However, the literature does not sufficiently cover the processes of cementation of heavy metals on cathode loading. A physico-chemical approach to this process is necessary to confirm the process of separation of heavy metal ions from wastewater in the form of sediment and the creation of new industrial wastewater treatment schemes. The composition of the loading is essential in galvanocoagulation neutralization, therefore, in order to determine the effect of the type of active loading, a carbon mineral sorbent (SGN) obtained from ores of cryptocrystalline graphite (Noginsky deposit of the Krasnoyarsk Territory) was used. The studies were carried out in a galvanocoagulation module by passing wastewater through a loading consisting of a mixture of iron shavings and granules of carbon mineral sorbent based on ores of cryptocrystalline graphite (SGN). At the same time, the air dispersed in the lower part of the device was bubbled through the loading. As a result of the operation of the Fe-SGN short-circuited galvanic cell, iron scrap was dissolved and its intensive oxidation to Fe3+ by air oxygen. The article considers the mechanism of galvanocoagulation neutralization of wastewater based on thermodynamic analysis of redox reactions occurring during galvanocoagulation wastewater treatment.
 Subject of the study: both model and real wastewater from the production of electroplating coatings containing copper, zinc and nickel ions with the following concentrations were used: =60 mg/dm3; =15 mg/dm3; =20 mg/dm3
 Materials and methods: galvanocoagulation neutralization using a short-circuited Fe-SGN galvanic cell (carbon mineral sorbent)
 Results: the physico-chemical patterns of the galvanocoagulation process of wastewater treatment have been studied and the thermodynamic parameters of heavy metal ion reduction reactions have been determined
 Conclusions. It has been experimentally established that it is possible to intensify the process of galvanocoagulation of wastewater containing heavy metal ions by using a carbon mineral sorbent as a cathode loading, which reduces the processing time with a high purification effect and a difficult-to-dissolve precipitate is formed.

In-situ polymerization of PANI nanocone array on PEN nanofibrous membranes for solar-driven interfacial evaporation

Solar-driven interfacial evaporation (SDIE) holds great potential for desalination, but it also poses challenges to application performance. Herein, a novel polyaniline (PANI) modified polyarylene ether nitrile (PEN) electrospun nanofibrous membranes (PANI@PEN) was developed by introducing PDA and CTAB, which increased the polymerization amount of PANI and controlled its morphology by sequential in-situ polymerization, aiming to enhance its SDIE comprehensive performance. This unique structure can generate multiple diffuse reflections under sunlight, resulting in the highest water evaporation rate of the nanofibrous membrane at 1.822 kg m−2 h−1, while evaporation rate at 1.527 kg m−2 h−1 for a 3.5 wt% sodium chloride solution. Due to the good flexibility of PEN polymer substrate, the obtained membranes can be easily arched, showcasing an interesting ability to collect salt through salt deposition. Meanwhile, PEN also provides a robust skeleton, endowed PANI@PENs with corrosion-resistant, capable of desalination in acidic media, purifying heavy metal ion solutions through evaporation, as well as good mechanical properties for reusability. The study potentially provides a strategy for utilizing dopamine and CTAB loaded on high-performance polymer nanofibrous membranes and the convenient in-situ polymerization to generate advanced photothermal PANI. This strategy paves a way to enable high-performance engineering polymer, PEN, with solar-thermal evaporation capabilities, further opening its potential applications in seawater desalination and industrial wastewater purification.

Interfacial Solar Evaporation: From Fundamental Research to Applications.

In the last decade, interfacial solar steam generation (ISSG), powered by natural sunlight garnered significant attention due to its great potential for low-cost and environmentally friendly clean water production in alignment with the global decarbonization efforts. This review aims to share the knowledge and engage with a broader readership about the current progress of ISSG technology and the facing challenges to promote further advancements toward practical applications. The first part of this review assesses the current strategies for enhancing the energy efficiency of ISSG systems, including optimizing light absorption, reducing energy losses, harvesting additional energy, and lowering evaporation enthalpy. Subsequently, the current challenges faced by ISSG technologies, notably salt accumulation and bio-fouling issues in practical applications, are elucidated and contemporary methods are discussed to overcome these challenges. In the end, potential applications of ISSG, ranging from initial seawater desalination and industrial wastewater purification to power generation, sterilization, soil remediation, and innovative concept of solar sea farm, are introduced, highlighting the promising potential of ISSG technology in contributing to sustainable and environmentally conscious practices. Based on the review and in-depth understanding of these aspects, the future research focuses are proposed to address potential issues in both fundamental research and practical applications.

Obtainment activated carbon by processing plum stones and using them in industrial wastewater purification

The article describes the technological features of the obtaining process of an import-substituting adsorbent with high adsorption properties from local raw materials, massively grown in our republic, waste plum stone, as well as the indicators of wastewater treatment from a pesticide and mineral fertilizer workshop. These adsorbents are intended for wastewater treatment from industrial enterprises. The research methods were carried out based on samples presented in the literature and standard GOST indicators. According to the results, carbon activated with steam at a temperature of 800 °C showed its effectiveness with higher adsorption properties compared to samples activated with acid and alkali. Therefore, this sample was used to purify wastewater from a pesticide and mineral fertilizer workshop. In conclusion, we can say that after thermal pyrolysis and steam treatment, the release of the elements O2 and Si from the plum pit leads to an increase in the amount of C and higher adsorption properties of the resulting activated carbon.

ОБЕЗВОЖИВАНИЕ НЕФТЕШЛАМОВ ОЧИСТНЫХ СООРУЖЕНИЙ С ПОСЛЕДУЮЩИМ ВОВЛЕЧЕНИЕМ В СТРОИТЕЛЬНЫЕ МАТЕРИАЛЫ

The physicochemical characteristics of oil sludge generated during the purification of industrial wastewater from oil refineries have been studied. Options for dehydration of oil sludge with sub-sequent inclusion in construction materials have been studied

Research Advances in Wood Composites in Applications of Industrial Wastewater Purification and Solar-Driven Seawater Desalination.

In recent years, the ecosystem has been seriously affected by sewage discharge and oil spill accidents. A series of issues (such as the continuous pollution of the ecological environment and the imminent exhaustion of freshwater resources) are becoming more and more unmanageable, resulting in a crisis of water quality and quantity. Therefore, studies on industrial wastewater purification and solar-driven seawater desalination based on wood composites have been widely considered as an important development direction. This paper comprehensively analyzes and summarizes the applications of wood composites in the fields of solar-driven seawater desalination and polluted water purification. In particular, the present situation of industrial wastewater containing heavy metal ions, microorganisms, aromatic dyes and oil stains and related problems of solar-driven seawater desalination are comprehensively analyzed and summarized. Generally, functional nanomaterials are loaded into the wood cell wall, from which lignin and hemicellulose are selectively removed. Alternatively, functional groups are modified on the basis of the molecular structure of the wood microchannels. Due to its three-dimensional (3D) pore structure and low thermal conductivity, wood is an ideal substrate material for industrial wastewater purification and solar-driven seawater desalination. Based on the study of objective conditions such as the preparation process, modification method and selection of photothermal conversion materials, the performances of the wood composites in filtration, adsorption and seawater desalination are analyzed in detail. In addition, this work points out the problems and possible solutions in applying wood composites to industrial wastewater purification and solar-driven seawater desalination.

Development and implementation of industrial wastewater treatment technologies

The results of the Igor Sikorsky Kyiv Polytechnic Institute the Department of Bioenergetics, Bioinformatics and Ecobiotechnology researches in two directions: 1 - research into the processes of physical and chemical purification of industrial wastewater of a number of industrial enterprises from antibiotics, heavy metal ions, synthetic surfactants, etc. pollutants, and the development of local cleaning technologies before discharging pre-treated wastewater into the city's drainage network; 2 – study of processes of biological wastewater treatment of industrial enterprises with deep removal of nitrogen and phosphorus compounds using immobilized microorganisms. The greatest decrease in the COD index was observed in the processes of coagulation and settling of wastewater of a pharmaceutical enterprise. The effects of purification according to the COD indicator in the case of using ferrous sulfate III were 76.0% and 72.2% for the initial values of COD of untreated wastewater, respectively, 90 and 120 mg/dm3. For biological purification, microorganisms immobilized on VIA carriers were used in oxygen conditions created in model bioreactors - anaerobic, anoxic, aerobic. To increase the biomass, we used nylon textured thread according to TU 6-06-S116-87 with a fiber diameter of 1.5-2.5 mm and a microfiber diameter of 100 μm. The specific surface area was 4000-5000 m2/m3. The average concentration of biomass in bioreactors by dry matter, g/dm3, was: in anaerobic I – 30; in anaerobic II – 24; in anoxic I - 16.8; in anoxic II - 5.4; in aerobic - 3.2. Biological treatment of industrial wastewater using immobilized microorganisms made it possible to obtain high pollutant removal effects. The indicators of purified wastewater were: COD - 50-80 mg/dm3; BODfull - 15-20 mg/dm3; suspended substances - up to 15 mg/dm3; compounds of nitrogen and phosphorus - within the norm for discharge into natural water bodies. The developed technologies were implemented at industrial enterprises, the savings in energy costs amounted to 40-45%, the high quality of purified water was ensured in accordance with the current standards for discharge into the city drainage system and into natural reservoirs.

CuInS2-MgO/S-doped biochar heterojunction for the efficient adsorption-photocatalytic elimination of cationic dye

CuInS2 and MgO-modified S-doped biochar (CIS-Mg/S-BC) was prepared by one-step pyrolysis to improve the adsorption-photocatalytic performance of biochar for in RhB removal. The photo-induced electrons and holes were efficiently separated and migrated at the junction interface among CuInS2, MgO, and S-doped biochar, enlarging visible light absorption. Langmuir and second-order models well described the adsorption isotherms and kinetics of S-BC-based hybrids, respectively. The best removal efficiency over 2d-CIS-Mg/S-BC for 400 mg L-1 RhB solution was 97.67 % within 120 min while reduced to 95.62 % after five cycles. Therefore, CIS-Mg/S-BC composites have a broad application prospect in industrial wastewater purification.

Efficient treatment of smelting wastewater: 3D nickel foam @MOF shatters the previous limitation, enabling high-throughput selective capture of arsenic to form non-homogeneous nuclei

A significant challenge in environmental remediation involves designing adsorbents that can effectively remove arsenic from smelting wastewater. This study aimed to address issues related to Metal-Organic Framework (MOF) pore blockage and insufficient active sites. To do this, we prepared MIL-101(Fe) and MIL-101(Cr) directly on three-dimensional nickel foam (NF) using a sustainable hydrothermal one-pot method. Using the NF as a carrier allowed for a uniform distribution of MIL-101(Fe) and MIL-101(Cr). This increased their contact area with the solution and enhanced the exposure of active sites. We investigated the adsorption capacities of trivalent and pentavalent arsenic by NF/MOFs through experiments and computational simulations. Our findings indicated that NF/MIL-101(Fe) and NF/MIL-101(Cr) adsorbed arsenic at concentrations of 152.65 mg/g and 132.615 mg/g, under conditions of room temperature and pH levels of 7 and 4, respectively. Analysis of the adsorption kinetics and thermodynamics revealed that the adsorption process for both adsorbents was chemical in nature, with monolayer adsorption being predominant. Molecular dynamics results indicated diffusion coefficients of 0.556667 × 10–6 for Fe3+ ions and 0.44 × 10–6 for Cr3+ ions. This suggests that NF/MIL-101(Fe) has a strong adsorption capacity. The proposed adsorption site model accurately predicted arsenic adsorption on the NF/MIL-101(Cr) and NF/MIL-101(Fe) structures. Given these properties, NF/MIL-101(Cr) and NF/MIL-101(Fe) are versatile materials with specificity and storage capacity for arsenic removal from smelting wastewater. Their potential in industrial wastewater purification is promising.

Development of nanostructured catalysts for catalytic oxidative water purification from organic impurities, including phenolic compounds

The purpose of this work was to create magnetic nanocatalysts that could be used for the oxidation of organic water pollutants – phenol and its derivatives – and to determine the physicochemical characteristics of the catalysts. The development of such active nanocomposite catalysts would solve the environmental problem in the Republic of Kazakhstan in the field of wastewater treatment from organic impurities, including phenols, and would also contribute to the subsequent creation of domestic production of oxygen-containing compounds, since almost the entire spectrum of oxygen-containing compounds for various industries is imported into the Republic. Nanosized magnetic composites based on Fe and Co were obtained by chemical deposition, in some cases, using polyethyleneimine and polyvinylpyrrolidone. It was shown that the interaction between nanoparticles and the polymer takes place in the case of a CoFe2O4 catalyst stabilized with polyvinylpyrrolidone or polyethyleneimine, which may indicate the efficient formation of nanocomposites. According to the IR study, for the CoFe2O4 nanocomposite stabilized with polyvinylpyrrolidone, the absorption bands at 735, 663, 649, 626 cm–1 are natural vibrations for the composite nanoparticles embedded in a polyvinylpyrrolidone matrix. The synthesized nanocomposites were tested in the oxidation of phenol with oxygen. The results demonstrate that the catalysts are promising both for the purification of industrial wastewater from phenol and for the synthesis of oxygen-containing compounds in the liquid phase under mild conditions.

Biosynthesis and characterization of silver nanoparticles generated from peels of Solanum tuberosum (potato) and their antibacterial and wastewater treatment potential

Global food production consumes a large fraction of energy budget, land area, and freshwater; however, a larger fraction of the produce is lost or unutilized, which has potential to produce useful products for human use. The biogenic synthesis of silver nanoparticles from such waste food appears to be a promising strategy. A conservative estimate of 70–140 thousand tons of potato peels is produced annually by food-chain companies globally; however, they are primarily utilized to produce substandard feed for livestock or manure. For the formation of highly profitable compounds, enhancement of value, and the process of extraction, such as nanocomposite, organic antioxidants, and organic meal inclusions, potato peels can be used as a cheap, productive, and readily available source of raw material. In the present research, silver nanoparticles (AgNPs) were extracted from the peels of potato (Solanum tuberosum). The fabrication of potato peel-derived AgNPs was established using UV-visible spectroscopy analysis. Approaches like X-ray diffraction (XRD), attenuated total reflection-infrared (ATR-IR) spectroscopy analysis, and field emission scanning electron microscopy (FESEM) were used to determine the characteristics of the AgNPs. Additionally, strains of Gram-positive bacteria such as Staphylococcus aureus (S. aureus) (ATCC 25923) and Gram-negative bacteria such as Escherichia coli (E. coli) (ATCC 25922) were used to determine the antibacterial activity of AgNPs via the disc diffusion technique. The antibacterial properties of AgNPs could help protect food from microbial contamination. Furthermore, AgNPs were tested for their potential application in purification of industrial wastewater. The results revealed that AgNPs derived from the potato peels could be used in industrial and biomedical applications and possess excellent antibacterial activity. Our research suggests that AgNPs can be extracted from a safe and ecofriendly fabrication technique from largely unused potato peels that have a great potential for inhibiting the bacterial growth and for the in situ purification of wastewater in the upcoming years. Therefore, besides value addition to the farm produce, such recycling of potato peels is likely to reduce the burden of the solid waste volumes in agro-centers, kitchen wastes, and food industries across the globe.

Development and study of adsorption properties of a new sulfur polyvinyl chloride cation exchanger for water treatment

The article analyses the sorption properties of thermally and chemically stable sulfonic cation exchange resin based on PVC. The article presents the temperature dependence of the analysis results of the sorption properties of Ca2+ and Mg2+ ions of sulfonated PVC. The results of the obtained sorption analysis are scientifically confirmed in the article. In addition, spatial Bode angle diagrams are presented, which provide very important scientific evidence of single maxima at intermediate frequencies. Purification of industrial waste water of enterprises was carried out with the help of the obtained sulfonic cation exchanger.

Preparation of flotation refined carbon from gasification slag

Highly efficient and environmentally friendly utilization of coal gasification slag is a hot research subject in the coal chemical industry at present. The preparation of activated carbon with a flotation refined carbon from gasification slag, a long flame coal, a high temperature coal tar containing 70% asphalt and an active agent in proper proportion was carried out. The influence of activation temperature and time on the surface properties and compressive strength of the produced activated carbon was investigated in a tube furnace. The oxygen functional group, pore structure and absorption performance of the produced activated carbon were characterized by FT-IR, N2 adsorption-desorption, SEM and iodine adsorption. The COD removal from biochemical waste water by the produced activated carbon was verified. The results show that the key factors for the effective formation and expansion of pore are the suitable activation temperature and time for the floatation refined carbon from gasification slag as the feedstock. The activated carbon prepared by carbonization at 550 °C for 30 min and steam activation at 950 °C for 2 h exhibits a crisscross morphology of organic carbon components and minerals. The surface area, pore capacity and average pore diameter are 566 m2/g, 0.5611 mL/g and 5.1 nm, respectively, with the characteristics of a concentrated pore distribution and a certain quantity of mesopore. Both iodine value (650 mg/g) and methylene blue value (128 mg/g) meet the requirements of the Chinese standard “Technical Specifications and Test Methods of Activated Carbon for Purification of Industrial Wastewater”. The COD in biochemical waste water treated by the activated carbon for 60 min with a solid-to-liquid ratio of 0.6 g/L can be reduced to lower than 30 mg/L, meeting the B class water quality of the Chinese standard “Integrated Discharge Standard of Water Pollutants” (DB11/307—2013).

Retracted: DE Oxidation-Fused Industrial Wastewater Purification Fuzzy Control and Simulation.

[This retracts the article DOI: 10.1155/2022/2843055.].

A novel phosphate rock-magnetic biochar for Pb[formula omitted] and Cd[formula omitted] removal in wastewater: Characterization, performance and mechanisms

The purification of industrial wastewater contaminated by lead (Pb) and cadmium (Cd) has become a global hot research topic at present. In this study, a novel phosphate rock-magnetic biochar (PR-MCLB) was prepared from phosphate rock (PR) and cow litter, and its removal efficiency and adsorption mechanisms for Pb2+ and Cd2+ in aqueous solution were explored. PR-MCLB maximum theoretical adsorption capacities (Qe,cal) of 451.24 and 120.87 mg g−1 at 25 °C for Pb2+ and Cd2+, respectively, which were approximately 1.5–42.4 and 1.1–21.0 times higher than the Qe,cal of phosphorus-modified or cow litter-derived biochar, respectively, as mentioned in previous studies. Acid conditions (pH 3.5–5.5) and coexisting cations (Ca2＋, Zn2+, Mg2+ (10–200 mg L−−1)) have almost no adverse effect on the performance of PR-MCLB. Mechanistic analysis showed that phosphate and carbonate on PR-MCLB played a crucial role in immobilization, with 54.03% of Pb2+ and 39.12% of Cd2+ being immobilized through mineral precipitate formation. A total of 21.24% of Pb2+ and 32.22% of Cd2+ were deposited on the PR-MCLB surface by ion exchange. This is followed by the cation-π interactions and surface complexation, contributing 9.11% and 11.10% for Pb2+ and 7.36% and 18.71% for Cd2+, respectively. These results indicated that PR-MCLB, as a efficient and environmentally friendly material, exhibits immense potential for application in the remediation of wastewater contaminated with Pb2+ and Cd2+.

CoFe2O4 with MoS2‐xOy Nanosheets as a Co‐catalyst for Enhanced Activation of Peroxydisulfate in Advanced Oxidation Processes

AbstractThe application of advanced oxidation processes (AOPs) based on sulfate radicals for degrading persistent organic pollutants faces challenges due to the inefficient activation of peroxydisulfate (PDS) oxidant. Herein, a composite CoFe2O4/MoS2‐xOy (CFM) catalyst consisting of CoFe2O4 nanoparticles uniformly dispersed on the nanosheets of oxygen‐incorporated MoS2 (MoS2‐xOy) with flower‐like morphology are fabricated through a facile two‐step hydrothermal method, which results in the enhanced activation of PDS and a highly efficient degradation of phenolic pollutants. The oxygen‐doping in MoS2‐xOy leads to unsaturated sulfur and active sites on the surface of MoS2 for accelerating the rate limiting step of FeIII/FeII reduction cycle in PDS‐CFM reaction. Aiming at the refractory organic pollutants in actual coking wastewater, CFM co‐catalyst is introduced into a hydrogel made up of polyvinyl alcohol (PVA) and coal‐tar pitch oxides (PO) to construct a multifunctional CFM@PO/PVA hydrogel. Upon hybrid CFM@PO/PVA, the coupling of the enhanced AOP with solar‐driven interfacial vapor generation (SIVG) technology contributes to the degradation efficiency, the removal rate of phenol in solution and the total organic carbon in coking wastewater can reach 98 % and 91 %, respectively. The integration of heterogeneous AOPs with SIVG system provides a feasible strategy for the eco‐friendly efficient purification of industrial wastewater.

Industrial Wastewater Purification Using Cow Bone and Saw Dust Filters

Poorly treated wastewater can adversely affect the existence of plants and animals. There is a need to look for low-cost filters to address the scarcity of water in rural areas surrounded by industrial wastewater. The present study investigates the use of low-cost filter for purification of industrial wastewater. Filters made from cow bone (CBF) and saw dust (SDF) were used to remove some impurities in wastewater. Wastewater from Ore Industrial Estate, Ondo State, Nigeria, are collected and ran through the filter, the physicochemical parameters were determined using standard method while metal content were determined using Atomic Absorption Spectrophotometer. The filter content before and after use were analyzed using Fourier Transformed Infrared (FTIR) Spectrometer. CBF reduces Electrical Conductivity (EC), Chloride and chemical oxygen demand COD of the wastewater appreciably. It removed 74 %, 70 %, 65 %, 68 % and 81 % of Mn, Ni, Cd, Pb, and Zn respectively while SDF removed 8 %, 14 %, 26 %, 17 % and 28 % of the same elements respectively. The C = O stretch was recorded at wavelength of 1646.31cm-1 before filtration and broad at 1640.19 cm-1 after filtration in CBF. Broad OH peak was recorded at 3750.84 cm−1 before filtration and 3674.41 cm−1 after filtration for saw dust filter (SDF). It was concluded that the spectral showed that some materials are removed from the water. The cow bone filter is more efficient than the saw dust filter.

Development of gradient-wetting Janus wood membrane with high-efficiency fog collection and oil-water separation

Conventional preparation of Janus membranes with asymmetric wettability focuses on the preparation of extreme hydrophilic side and hydrophobic side, but suffers from pore clogging, low liquid transfer and collection efficiency and short service life. In this study, Janus wood (JW) with a continuous wettability gradient was created throughunidirectional vacuum impregnation of a hydrophobic solvent after the delignification of wood. Digital image correlation (DIC) and layer-by-layer contact angle assessment were utilized to examine the thickness-dependent wettability gradient of the JW membrane. The JW membrane completed the modification of the cell walls without blocking the cell lumens. The presence of wettability gradient in the JW membrane effectively reduced the capillary force of liquid penetration, resulting in decreased adhesion and stagnation of liquid on the membrane surface, and increased flow rate and transport efficiency. Based on the continuous wettability change of the JW membrane, the JW membrane was endowed with the ability to act as a “unidirectional valve” to enable continuous and rapid directional transport of liquids. The mechanical properties of the JW membrane prepared by the unidirectional introduction method were significantly improved, rendering them highly stable and environmentally durable. The fog collection efficiency of the JW membrane was maintained at 97.7% over 10 repeated use cycles. For light oil/water and heavy oil/water mixtures, JW membrane maintained an efficiency of 99.6% or higher. Unlike conventional surface modification methods, the unidirectional introduction method proved practical and effective for modifying the JW membrane in the thickness direction. Furthermore, the prepared JW membrane was sustainable, inexpensive, durable, and environmentally friendly. This study provides a wide range of potential applications in fields such as droplet manipulation, multi-liquid separation, industrial wastewater purification, and microfluidics.

Enhanced piezocatalytic activity of BiFeO3 hollow spheres with surface iodine-grafting

The insufficient active sites, low separation efficiency of free carriers and poor capacity to generate active free radicals are limitations of asymmetrical BiFeO3 in piezocatalysis. To address these issues, BiFeO3 hollow nanospheres with exposed abundant catalytic active sites were fabricated via a solvothermal method for the first time. In addition, surface iodine-grafting was introduced, resulting in a local electric field and the conduction band potential of BiFeO3 closer to the O2/·O2– redox potential (-0.33 eV). It facilitated charge transmission and active species generation to remove bisphenol A under ultrasonic vibration. Thus, the iodine-grafted BiFeO3 hollow nanospheres could completely degrade 20 mL bisphenol A (10 ppm) within 60 min with a relatively fast rate constant of 0.153 min−1, which was 4.5 times higher than that of un-grafted BiFeO3. This work provides a feasible approach to construct efficient piezocatalysts for industrial wastewater purification.