Wastewater Treatment In Areas Research Articles

Synergistically active Fe3O4 magnetic and EDTA modified cellulose cotton fabric using chemical method and their effective pollutants removal ability from wastewater

A unique combination of cotton fabric (CF) with a mixture of EDTA and APTES Fe3O4 magnetic particles was developed and utilized for the first time as an adsorbent for removing pollutants from wastewater. Initially, Fe3O4 was synthesized using the co-precipitation method. Further, the surface of Fe3O4 was modified by introducing amino functional groups through a reaction with APTES, resulting in Fe3O4-NH2. Following this, the surface of carbon fiber (CF) was altered using ethylenediaminetetraacetic acid (EDTA) to create CF@EDTA. Through the use of EDC-HCl and NHS, Fe3O4-NH2 was attached to the surface of CF@EDTA, resulting in the final product CF@EDTA/Fe3O4. Subsequently, the prepared CF@EDTA/Fe3O4 was utilized to adsorb metal pollutants from wastewater, with a thorough analysis conducted using various characterization techniques including FTIR, SEM, EDX, XRD, VSM, and XPS to study the materials. The study specifically aimed to assess the adsorption performance of our cotton-based material towards As(III) and Cr3+ metal ions. The pH study was also performed. Results indicated that the material exhibited an adsorption capacity of approximately 714 mg/g for As(III) ions and 708 mg/g for Cr3+ ions. The Langmuir and Freundlich models, as well as pseudo-first and second-order models were also analyzed. The Langmuir and pseudo-second-order models were found to best fit the data. In terms of regeneration and reusability, the materials showed straightforward regeneration and recyclability for up to 15 cycles. The remarkable adsorption capacity, combined with the unique blend of cotton and Fe3O4 magnet, along with its recyclability, positions our material CF@EDTA/Fe3O4 as a promising contender for wastewater treatment and other significant areas in water research.

Green and facile fabrication of robust calcium alginate sponges via thermally bonded nonwoven induced freeze-drying for dressing applications

Alginate sponges have been widely studied in areas of wound healing, drug release, tissue engineering, and wastewater treatment due to their potential biological activity, biocompatibility, high porosity, and large surface area. However, their poor mechanical properties greatly limit the practical applications of alginate sponge. In this study, a structurally controllable and high-performance sponge material preparation strategy was proposed by optimizing the structure of the freeze-dried calcium alginate (CA) sponge using fluffy and porous thermally bonded nonwovens (NWs). The performance of composite sponges (CA@NWs) prepared at different pre-freezing temperatures and concentrations were tested. The results showed that the NWs skeleton could improve the formation structure and size stability of the freeze-dried CA sponge, making it have good fluid absorption, moisture permeability, moisture retention, and wet state mechanical properties. The RF-1.0-CA@NWs sponge had the highest fluid absorption rate of 1415 %. The wet state RF-1.5-CA@NWs sponge had tensile strengths of 1.913 MPa and 0.465 MPa in the MD and CD directions, respectively, which was about 95 times higher than that of the wet state pure CA sponge.

Airborne antibiotic resistome and microbiome in pharmaceutical factories

Antimicrobial resistance is considered to be one of the biggest public health problems, and airborne transmission is an important but under-appreciated pathway for the spread of antibiotic resistance genes (ARGs) in the environment. Previous research has shown pharmaceutical factories to be a major source of ARGs and antibiotic resistant bacteria (ARB) in the surrounding receiving water and soil environments. Pharmaceutical factories are hotspots of antibiotic resistance, but the atmospheric transmission and its environmental risk remain more concerns. Here, we conducted a metagenomic investigation into the airborne microbiome and resistome in three pharmaceutical factories in China. Soil (average: 38.45%) and wastewater (average: 28.53%) were major contributors of airborne resistome. ARGs (vanR/vanS, blaOXA, and CfxA) conferring resistance to critically important clinically used antibiotics were identified in the air samples. The wastewater treatment area had significantly higher relative abundances of ARGs (average: 0.64 copies/16S rRNA). Approximately 28.2% of the detected airborne ARGs were found to be associated with plasmids, and this increased to about 50% in the wastewater treatment area. We have compiled a list of high-risk airborne ARGs found in pharmaceutical factories. Moreover, A total of 1,043 viral operational taxonomic units were identified and linked to 47 family-group taxa. Different CRISPR-Cas immune systems have been identified in bacterial hosts in response to phage infection. Similarly, higher phage abundance (average: 2451.70 PPM) was found in the air of the wastewater treatment area. Our data provide insights into the antibiotic resistance gene profiles and microbiome (bacterial and non-bacterial) in pharmaceutical factories and reveal the potential role of horizontal transfer in the spread of airborne ARGs, with implications for human and animal health.

Greece’s current water and wastewater regulations and the risks they pose to environmental hygiene and public health, as recommended by the European Union Commission

To address emerging environmental issues, the European Union (EU) regularly updates its directives and regulations in the areas of wastewater treatment, water reuse, and water quality. The plan specifies standards for safe water reuse as well as quality requirements for treated wastewater. Legislation and regulations in Greece pertaining to wastewater management and water reuse assess how well-functioning current methods are at maintaining water quality, cutting pollution, and protecting public health. Analyze any unique challenges or successes in putting current laws into effect and keeping them in place. Determine areas of agreement and disagreement between EU plan and Greek legislation. EU proposal’s possible effects on Greece’s infrastructure, adoption of new technologies, and financial implications. This study is a perspective qualitative analysis. Selection of legislation, outline the criteria used for selecting the relevant legislation from EU and Greece. Data sources from obtained the legislation texts. Official government documents, legal databases, and reputable sources. Data variables extracted from the legislation, focusing on aspects related to environmental hygiene and public health risks. Comparative framework used to compare EU commission proposal with existing legislation in Greece. Evaluate the environmental hazards and problems associated with present wastewater management practices in Greece in terms of their potential influence on water quality, ecosystems, public health, and promote environmental hygiene.

A comprehensive review of synthesis, characterization, and applications of aluminosilicate materials-based geopolymers

The increase in the cement industry's production, especially the production of Ordinary Portland Cement (OPC), increases the amount of CO2 released into the atmosphere, one of the main greenhouse gases responsible for global warming, with harmful effects on the environment and human health. Against this background, geopolymer concrete is a new type of inorganic polymer material that has attracted the attention of researchers in the building area, due to recycling waste by-products to replace OPC and reducing greenhouse gas (CO2) emissions during its manufacture. It also exhibits better mechanical, thermal, chemical, and electrical properties than OPC-based concrete. In the same environmental context, this material has also attracted the attention of researchers in the wastewater treatment area, because of its specific surface area and the capability of adsorption, photodegradation, and encapsulation of organic and inorganic pollutants. The principal focus of this paper is to provide an in-depth overview of the works that have been undertaken to explore geopolymer-type materials. The paper will attempt to develop a comprehensive database, based on the last research works published between 2010 and 2023 with about 247 references, which explains the elaboration, characterization, and application of these materials in several fields. Therefore, it is estimated that geopolymer composites are promising future candidates for recycling industrial solid waste, the partial or total replacement of OPCs in the construction industry, and the development of adsorbents and catalysts for wastewater treatment.

Review on emerging trends and challenges in the modification of xanthan gum for various applications

This review explores the realm of structural modifications and broad spectrum of their potential applications, with a special focus on the synthesis of xanthan gum derivatives through graft copolymerization methods. It delves into the creation of these derivatives by attaching functional groups (-OH and –COOH) to xanthan gum, utilizing a variety of initiators for grafting, and examining their diverse applications, especially in the areas of food packaging, pharmaceuticals, wastewater treatment, and antimicrobial activities. Xanthan gum is a biocompatible, biodegradable, less toxic, bioactive, and cost-effective natural polymer derived from Xanthomonas species. The native properties of xanthan gum can be improved by cross-linking, grafting, curing, blending, and various modification techniques. Grafted xanthan gum has excellent biodegradability, metal binding, dye adsorption, immunological properties, and wound healing ability. Owing to its remarkable properties, such as biocompatibility and its ability to form gels resembling the extracellular matrix of tissues, modified xanthan gum finds extensive utility across biomedicine, engineering, and the food industry. Furthermore, the review also covers various modified derivatives of xanthan gum that exhibit excellent biodegradability, metal binding, dye adsorption, immunological properties, and wound healing abilities. These applications could serve as important resources for a wide range of industries in future product development.

Adsorption of crystal violet dye from synthetic wastewater by ball-milled royal palm leaf sheath

The current study shows that using a batch approach to remove crystal violet dye from synthetic wastewater is feasible when using royal palm leaf sheath powder as an adsorbent. In order to investigate the effects of many parameters, including starting concentration, pH effect, dye concentration, adsorbent dose, contact time, and temperature, experiments were carried out under various operating conditions. Maximum removal was obtained at pH 6 and at a concentration of 100 ppm, which are considered as ideal values. The influence of pH and dye concentration was shown to be substantial. Langmuir, Freundlich, and Temkin isotherm models were fitted to equilibrium data. The Langmuir isotherm model, which showed a maximum monolayer adsorption capacity of 454.5455 mg/g, best described the equilibrium data. The Pseudo-second-order kinetic model was found to closely resemble rather than the first-order and intra-particle diffusion models. Standard enthalpy (∆H◦), entropy (∆S◦), and free energy (∆G◦) were evaluated as thermodynamic parameters. It was discovered that the adsorption contact was endothermic in nature. The outcomes highlight the applicability of the inexpensive, locally accessible adsorbent in the specialty area of wastewater treatment and can be used in commercial dye-enriched effluent.

Environmental Management of Ecuador’s Business Sector in the Fight against Climate Change

The private sector is part of the United Nations Global Compact, which promotes the voluntary participation of organizations to implement environmental care strategies. The purpose of this article is to examine the performance of Ecuadorian companies in regard to environmental management, especially in the fight against climate change, considering the economic sectors (manufacturing, mining, commerce, construction and services). Figures from the National Institute of Statistics and the Census of Ecuador (2020) are used, including descriptive statistics and cross-tabulations with Cramer’s V index. The results show that approximately 5% of companies had the ISO 14001:2015 certification. In the seven actions against climate change considered, the proportion of companies that did not consider them to be current expenses predominated. Cramer’s V index, for associating the economic sector and the environmental spend, revealed that certain economic sectors (manufacturing and mining) are contributing significantly to environmental management spending in the areas of air, soil, wastewater and waste treatment, while no economic sector dominates the others in areas such as radiation treatment, the use of mineral or energy resources and water resources.

Numerical schemes for a moving-boundary convection-diffusion-reaction model of sequencing batch reactors

Sequencing batch reactors (SBRs) are devices widely used in wastewater treatment, chemical engineering, and other areas. They allow for the sedimentation and compression of solid particles of biomass simultaneously with biochemical reactions with nutrients dissolved in the liquid. The kinetics of these reactions may be given by one of the established activated sludge models (ASMx). An SBR is operated in various stages and is equipped with a movable extraction and fill device and a discharge opening. A one-dimensional model of this unit can be formulated as a moving-boundary problem for a degenerating system of convection-diffusion-reaction equations whose unknowns are the concentrations of the components forming the solid and liquid phases, respectively. This model is transformed to a fixed computational domain and is discretized by an explicit monotone scheme along with an alternative semi-implicit variant. The semi-implicit variant is based on solving, during each time step, a system of nonlinear equations for the total solids concentration followed by the solution of linear systems for the solid component percentages and liquid component concentrations. It is demonstrated that the semi-implicit scheme is well posed and that both variants produce approximations that satisfy an invariant region principle: solids concentrations are nonnegative and less or equal to a set maximal one, percentages are nonnegative and sum up to one, and substrate concentrations are nonnegative. These properties are achieved under a Courant-Friedrichs-Lewy (CFL) condition that is less restrictive for the semi-implicit than for the explicit variant. Numerical examples with realistic parameters illustrate that as a consequence, the semi-implicit variant is more efficient than the explicit one.

Heterogeneous Activation of Persulfate by Nickel Oxide/Strontium Carbonate Composite for Sulfamethoxazole Degradation in Water

The development of efficient heterogeneous persulfate activators is one of the main research topics in the wastewater treatment area. The present work deals with the heterogeneous activation of sodium persulfate (SPS) using nickel oxide/strontium carbonate (NiO/SrCO3) for the degradation of sulfamethoxazole (SMX), a representative compound from the group of antibiotics. Results showed that NiO/SrCO3 exhibited high performance towards the activation of SPS, leading to SMX elimination in brief time spans. The impact of SPS (25–100 mg/L), NiO/SrCO3 (50–250 mg/L), and SMX (0.25–3.00 mg/L) concentration, and initial pH on the decomposition of SMX was further examined. Experiments were also conducted in real matrices such as secondary effluent and bottled water, revealing the existence of retarding phenomena compared to ultrapure water. This behavior was further investigated with the addition of bicarbonates, chlorides, or humic acid in ultrapure water. It was found that organic matter significantly hampered SMX removal. The role of the main radicals (hydroxyl and sulfate radicals) was determined using appropriate radical traps (methanol and tert-butanol). These quenching experiments combined with the conducted electrochemical measurements revealed that both a radical and a non-radical mechanism contribute to the decomposition of SMX.

Novel-supported ionic liquid membranes for an effective removal of pentachlorophenol from wastewater

Recently ionic liquids (ILs) have been useful in many areas of wastewater treatment and separation processes in environmental engineering, such as supported ionic liquid membranes (SILM) based separations and solvent extraction applications. In this work novel ILs, namely 1-butyl-2,3-dimethyl imidazolium hexafluorophosphate [C4DMIM][PF6], tetrabutyl–phosphonium exafluorophosphate [TBP][PF6] were immobilized on PVDF (polyvinylidene fluoride) membrane for the removal of organic pollutant such as pentachlorophenol (PCP) from the water phase by SILM. Operating conditions like pH, feed and permeate concentration, membrane flux, and the mechanism was also studied. The interactions of H+ bonding, hydrophobic interactions, and carbon–π bonding interactions are explained via the SILM transport mechanism. The membranes were characterized by SEM, EDX, and FTIR analysis. In the experimental study, a high zetapotential of −93.24 mV was achieved, which is an indication of the excellent stability of SILM. At a pH of 4, [TBP][PF6] had the highest penetration rate of 87%. In contrast, [C4DMIM][PF6] yielded 79% after 30 h of experimentation at the feed pH 4. Similarly, after 30 h, [TBP][PF6] got the highest rate of permeation (80.50%), followed by [C4DMIM][PF6] (73.00%). The 0.1 M NaOH was used as a stripping agent in this study. PCP was successfully separated from the aqueous phase using two different hydrophobic ionic liquids as [C4DMIM][PF6] and [TBP][PF6]. This SILM technique has the potential in the future for further developments and for extracting organic contaminants from wastewater on a laboratory or industrial scale.

Assessing the impact of COVID-19 restrictions on the microbial quality of an urban water catchment and the associated probability of waterborne infections

The World Health Organization reported that COVID-19 cases reached 611,421,786 globally by September 23, 2022. Six months after the first reported case, the disease had spread rapidly, reaching pandemic status, leading to numerous preventive measures to curb the spread, including a complete shutdown of many activities worldwide. Such restrictions affected services like waste management, resulting in waste accumulation in many communities and increased water pollution. Therefore, the current study investigated if lockdown impacted surface water microbial quality within an urban water catchment in South Africa. Using quantitative microbial risk assessment, the study further assessed changes in the probability of infection (Pi) with gastrointestinal illnesses from exposure to polluted water in the catchment. Escherichia coli data for 2019, 2020 and 2021 – pre-COVID, lockdown, and post-lockdown periods, respectively – were collected from the area's wastewater treatment management authorities. The Pi was determined using a beta-Poisson model. Mean overall E. coli counts ranged from 2.93 ± 0.16 to 5.30 ± 1.07 Log10 MPN/100 mL. There was an overall statistically significant increase in microbial counts from 2019 to 2021. However, this difference was only accounted for between 2019 and 2021 (p = 0.008); the increase was insignificant between 2019 and 2020, and 2020 and 2021. The Pi revealed a similar trend for incidental ingestion of 100 mL and 1 mL of polluted water. No statistically significant difference was observed between the years based on multiple exposures. Although the overall microbial load and Pi estimated within the catchment exceeded the local and international limits recommended for safe use by humans, especially for drinking and recreation, these were not significantly affected by the COVID-19 restrictions. Nevertheless, these could still represent a health hazard to immunocompromised individuals using such water for personal and household hygiene, especially in informal settlements without access to water and sanitation services.

Using carbon dioxide-added microalgal-bacterial granular sludge for carbon-neutral municipal wastewater treatment under outdoor conditions: Performance, granule characteristics and environmental sustainability

Microalgal-bacterial granular sludge (MBGS) process has a gorgeous prospect for municipal wastewater treatment, but the research on the treatment of complex organic wastewater by MBGS process with CO2 addition under outdoor conditions is not enough. Therefore, this paper evaluated the feasibility of CO2-added MBGS process for complex organic wastewater disposal under natural day-night cycles. The results showed that the addition of CO2 overall improved the removal efficiency of pollutants. Typically, the removal efficiency of total phosphorus increased averagely from 88.5 % to 95.0 % in 12-h day cycle and from 26.2 % to 45.3 % in 12-h night cycle. The addition of CO2 increased the size of MBGS from 1.0 mm to 16.5 mm within 30 days due to extracellular polymeric substances secretion and the dominant filamentous microalgae on granules. The decrease of catalase activity and malondialdehyde content indicated that CO2 reduced oxidative damage and maintained the normal growth of MBGS. Further estimates of the collected gas showed that CO2-added MBGS process could reduce global CO2 emissions by one hundred million tons per year. This study is expected to contribute to the goal of carbon neutrality in the area of wastewater treatment by MBGS process.

Co-Removal Effect and Mechanism of Cr(VI) and Cd(II) by Biochar-Supported Sulfide-Modified Nanoscale Zero-Valent Iron in a Binary System.

This study aimed to explore the co-removal effect and mechanism of Cr(VI) and Cd(II) with an optimized synthetic material. The toxicity and accumulation characteristics of Cr(VI) and Cd(II) encountered in wastewater treatment areas present significant challenges. In this work, a rational assembly of sulfide-modified nanoscale zero-valent iron (SnZVI) was introduced into a biochar (BC), and a Cr(VI)–Cd(II) binary system adsorbent with high efficiency was synthesized. When the preparation temperature of the BC was 600 °C, the molar ratio of S/Fe was 0.3, the mass ratio of BC/SnZVI was 1, and the best adsorption capacities of BC-SnZVI for Cr(VI) and Cd(II) in the binary system were 58.87 mg/g and 32.55 mg/g, respectively. In addition, the adsorption mechanism of BC-SnZVI on the Cr(VI)-Cd(II) binary system was revealed in depth by co-removal experiments, indicating that the coexistence of Cd(II) could promote the removal of Cr(VI) by 9.20%, while the coexistence of Cr(VI) could inhibit the removal of Cd(II) by 43.47%. This work provides a new pathway for the adsorption of Cr(VI) and Cd(II) in binary systems, suggesting that BC-SnZVI shows great potential for the co-removal of Cr(VI) and Cd(II) in wastewater.

Social knowledge, attitudes, and perceptions on wastewater treatment, technologies, and reuse in Tanzania

Abstract This study assessed the social knowledge, attitude, and perceptions (KAPs) on wastewater treatment, the technologies involved, and its reuse across different wastewater treatment areas in four regions of Tanzania. We used both quantitative and qualitative data collection methods in a household-level questionnaire (n=327) with structured and semi-structured questions, which involved face-to-face interviews and observation. Our results show that social KAPs surrounding wastewater treatment and reuse were sufficient based on KAP scores achieved from asked questions. However, the general knowledge on treatment technologies, processes, and reuse risks was still low. Of the respondents, over 50% approved using treated wastewater in various applications, while the majority (93%) were reluctant if the application involved direct contact with the water. Furthermore, over 90% of interviewees did not know the technologies used to treat wastewater and the potential health risks associated with its use (59%). Multivariate analysis of variance revealed significant differences (P<0.05) in the KAPs on treated wastewater across different studied demographic variables, i.e., age, sex, and education level. Therefore, we recommend that more effort be spent on providing public education about the potential of wastewater treatment and existing technologies in order to facilitate their adoption for the community's and environment's benefit.

Synergistic activation of peroxymonosulfate for efficient aqueous p-nitrophenol degradation with Cu(II) and Ag(I) in Ag2Cu2O3

Recently, the development of efficient mixed metal oxide catalysts for organic pollutants degradation via peroxymonosulfate (PMS) activation is a hot topic in the area of wastewater treatment. In this work, the silver-copper mixed-oxide, Ag2Cu2O3 (ACO) was reported for the first time as a highly active catalyst for removing organic pollutants in the presence of PMS. ACO was successfully synthesized from Ag+ and Cu2+ ions at 60 °C, and its structure was strongly influenced by the temperature. The catalyst could almost completely remove p-nitrophenol and other pollutants with 0.65 mM PMS after 20 min, and also exhibited satisfactory stability and recyclability. The system efficiency was shown to vary with the concentration of PMS and catalyst, as well as solution pH. Scavenger experiment and EPR analysis indicated that radicals produced by the oxidation of Ag(I) and Cu(I) with PMS could promote degradation reaction. The synergistic effect between Cu and Ag in the bimetallic catalyst was demonstrated to contribute to the high performance: Cu(II)-O-Ag(I) bonds promote the conversion of Cu(II) species to Cu(I) through reaction with PMS, and facilitate the oxidation of Cu(I) and Ag(I) by PMS to generate active radicals. The study provides a feasible strategy to design efficient and stable bimetal oxide catalysts for PMS activation.

Treatment of wastewater containing methyl orange dye by fluidized three dimensional electrochemical oxidation process integrated with chemical oxidation and adsorption

The integrated high-efficiency treatment technology for dye industry wastewater is one of the current research hot topic in industrial wastewater treatment area. This article reports a new fluidized three-dimensional electrochemical treatment process integrating activated carbon adsorption, direct electro-oxidation and ·OH oxidation. In the process, activated carbon is polarized in a fluidized bed electrochemical reactor to enhance the direct electro-oxidation and ·OH oxidation, and there is a synergistic effect of effective adsorption and electrochemical oxidation to strengthen the treatment efficiency. When 200 mg/L methyl orange is processed, its removal rate reaches 99.9% in 30min, and the synergistic efficiency is 57.3%. After 8 cycles of activated carbon reusage in the process, the removal rate of methyl orange still kept at 89.2%. It is also founded that the activated carbon maintains 64.5% of its original adsorption capacity during the cycle. These results shows its interesting application potential in the fields of high-efficiency, low-cost and green treatment of various industrial organic wastewaters. Further improvements should focus on the development of continuous operation model and the improvement of the activated carbon electro-catalytic performance and the practical regeneration ways of the activated carbon particle electrodes.

Bisphenol S degradation via persulfate activation under UV-LED using mixed catalysts: Synergistic effect of Cu–TiO2 and Zn–TiO2 for catalysis

A photocatalyst composed of Zn–TiO2 and Cu–TiO2 through simple physical mixing was used to activate persulfate(PS) for Bisphenol S (BPS) degradation. Zn–TiO2 and Cu–TiO2 were prepared with a sol gel method and were characterized by X-ray diffraction (XRD), Raman, Transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The two catalysts have shown an obvious synergistic effect in the photocatalytic degradation process. When 5 mM persulfate and 0.3 g/L catalyst were used, the removal rate of mixed catalyst (0.2 g/L Zn–TiO2 and 0.1 g/L Cu–TiO2) is 100 % in 18 min, which is significantly better than that of 0.3 g/L Zn–TiO2(58 %) and 0.3 g/L Cu–TiO2(90 %). Typically, the effects of various operation parameters, including the ratio of Cu–TiO2/Zn–TiO2, catalyst dosage, persulfate dosage, initial concentration of BPS, and initial solution pH, were examined. Reactive oxygen species (ROS) in the UV/mixed catalyst/PS process was identified by scavenger and electron paramagnetic resonance (EPR) tests. The superoxide radicals generated by both Zn–TiO2 and the hydrolysis of persulfate in the system could accelerate the Cu (II)/Cu(I) redox cycles and results in the synergistic effect. This study proposed a new and effective way to improve the reaction by simply combining two catalysts, and unraveled the mechanism behind the synergistic effect, which could provide new ideas to use the catalyst more effectively for wastewater treatment or other areas.

Electrocoagulation Treatment of Oily Wastewater in the Oil Industry

Electrocoagulation has turned out to be a rapidly growing area of wastewater treatment due toits ability to remove contaminants that are generally more difficult to remove by filtration orchemical treatment systems. These pollutants may include emulsified oil, petroleumhydrocarbons, suspended solids, and heavy metals. In this novel technology, metal cations arereleased into the wastewater through dissolving metal electrodes. Simultaneously, beneficialside reactions can help in removing flocculated material from the water.Oily wastewater represents a dangerous threat when discharged to the environment; thereforetreating it becomes vital in oil industry. This research has investigated electrocoagulation as asimple, effective and economic technique for treatment of such wastewater. Bench scale reactorwas used to evaluate the factors that may affect the treatment of oily wastewater. Aluminumwas used as a sacrificial anode. Electrodes were arranged at different configurations to selectthe optimal one. Other tested operation parameters include time of treatment, current density,distance between the electrodes, and the electrolyte concentration of the emulsion. Theexperimental results indicated that electrocoagulation was very efficient and able to achieve94% turbidity removal in less 60 min, pH:7, current density of 45 (A/m2).Also the effect of initial concentration of oil (100-1000 ppm) in wastewater, applied voltage(10-20 v), the dose of NaCl electrolyte (0-1 g) and temperature (35-60 oC) were optimized.What distinguishes this work is the the type of the electrodes configuration. Circular horizontalAl/Al electrodes (Ø12 cm) with 17 holes (Ø7 mm) have been found to give the bestelectrocoagulation environment and thus optimum results. The associated electrical energyconsumption is 1.6 kW h/m3 for flotation times of 60 min.

Design of Porous Membranes by Liquid Gating Technology

ConspectusPorous membranes are playing paramount roles in the areas of wastewater treatment, chemical analysis, energy storage and conversion, flexible devices, and biomedical engineering. Despite their significance in the above fields, the performances of the porous membrane will be weakened due to the inevitable membrane fouling. Solid surfaces or pores of the membranes are easily contaminated or even clogged due to the absorption of small molecules or the accumulation of fine particles, which lower the flux of fluid transport over time, reduce the separation efficiency, shorten the lifetime of the membranes, and increase the operational costs. In addition, the defects in membranes also hinder their applications to some extent. The above-mentioned limitations all arise from the intrinsic properties of the solid surfaces of the membranes. To solve these challenges, liquid gating technology was proposed, which utilizes the capillary-stabilized functional liquid as a pressure-driven, reversible, and reconfigurable gate to fill and seal the pores on demand. Using liquid gating technology, multiphase transportation in the membrane can be modulated with exceptional antifouling and energy-saving manners due to the defect-free molecular-smooth liquid interface. Moreover, the further responsive interface design accelerated the development of liquid gating membranes and their practical applications to a great extent. In recent years, the concept of the liquid gating membrane has become a reality through developing various porous membranes by the rational selection and design of the two essential parts of the composite membranes: the solid porous matrix and the gating liquid. These membranes expand the basic scientific issues of the traditional membranes from the solid–liquid/gas interface to the solid–liquid–liquid/gas interface and bring more possibilities for the applications of porous membranes. With properties and advantages of antifouling, anticorrosion, enhanced transparency, energy-saving, and stability, these porous membranes have shown various applications in multiphase separation, biomedical catheters, chemical detection, mobile valves, microscale flow control, etc.In this Account, we provide a systematic review of our group’s recent progresses in the design and applications of porous membranes with liquid gating technology. First, we give a comprehensive introduction to the liquid gating technology, followed by further details on how to design porous membranes through liquid gating technology and properties and advantages of the porous membranes. Second, we discuss the applications of these porous membranes in the fields of multiphase separation, biomedical catheters, chemical detection, mobile valves, and microscale flow control. Third, we conclude the Account by describing the current challenges and future directions of the field.