Field Of Wastewater Treatment Research Articles

2D MoS2 nanosheets supported CoFe2O4 nanoparticles mediated persulfate activation for antibiotic removal

Advanced oxidation technology based on persulfate activation has caused extensive concern in the field of wastewater treatment. Nevertheless, this new technology is limited to the low catalytic efficiency and poor recovery of powder catalysts. Herein, we successfully synthesized MoS2 surface-supported CoFe2O4 nanoparticles composite catalyst employing a simple hydrothermal method. Compared with other systems, the performance of TC degradation was significantly improved by CoFe2O4/MoS2/PS system. Additionally, the influence of solution pH, catalyst dosage, PS dosage, and co-existing ions on the degradation process were studied. Both free radical (O2•−, •OH, SO4•−) and non-free radical (1O2) pathways coexisted in the catalytic degradation of TC on the account of radicals quenching experiments and electron spin resonance (ESR) technique. Additionally, the degradation pollutants were confirmed to display obvious decrease in toxicity based on microbial toxicology tests. Besides, CoFe2O4/MoS2 nanocomposite displays good magnetic recovery performance due to the introduction of CoFe2O4. In summary, this research provides a solid foundation for the application of magnetic CoFe2O4/MoS2 nanocomposite in the treatment of antibiotic wastewater.

High-performance thin film composite forward osmosis membrane for efficient rejection of antimony and phenol from wastewater: Characterization, performance, and MD-DFT simulation

The effective removal of heavy metals and phenolic pollutants from aqueous solutions has received widespread attention in the field of wastewater treatment. In this work, a novel PAN/CNTs/UiO-66-NH2 modified forward osmosis (FO) membrane was prepared for efficient removal of antimony (Sb) and phenol from wastewater. The membrane was synthesized using a facile and cost-effective method. The PAN/CNTs substrate membrane was prepared using electrospinning technology, and UiO-66-NH2 MOF particles were loaded onto the surface of the active layer during the interfacial polymerization (IP) process. The presence of CNTs in the spinning solution regulated the pore structure and properties of nanofibers. Characterization of the membrane confirmed its unique structure and enhanced properties. When the CNTs addition was 0.01 g, and UiO-66-NH2 addition was 0.05 wt%, the FO membrane exhibited the optimal operational performance. In the AL-FS mode, the water flux, reverse salt flux (RSF), and Js/Jw ratio were 14.68 LMH, 0.17 gMH, and 0.01 g/L, respectively. As a comparison, the water flux, RSF, and Js/Jw ratio were 21.19 LMH, 0.65 gMH, and 0.032 g/L in the AL-DS mode, respectively. Simultaneously, efficient removal of antimony and phenol was achieved in both modes, with antimony removal efficiencies of 99.26 % and 97.98 %, and phenol removal efficiencies of 96.61 % and 93.18 %, respectively. The modified membrane exhibited excellent performance in rejecting Sb and phenol. Molecular dynamics simulations and density functional theory calculations provide theoretical support for the excellent performance of membranes. The membrane demonstrated a high water flux, making it promising for practical applications. Additionally, it exhibited remarkably low reverse salt flux, highlighting its suitability for desalination processes. The exceptional removal efficiency of Sb and phenol, coupled with the membrane's impressive hydraulic performance, makes it a promising candidate for the treatment of industrial effluents containing these challenging contaminants. The results presented in this study underscore the potential of PAN/CNTs/UiO-66-NH2 FO membranes as an advanced solution for addressing water pollution challenges.

High capacities of carbon capture and photosynthesis of a novel organic carbon-fixing microalgae in municipal wastewater: From mutagenesis, screening, ability evaluation to mechanism analysis

The development of wastewater treatment processes capable of reducing and fixing carbon is currently a hot topic in the wastewater treatment field. Microalgae possess a natural carbon-fixing advantage, and microalgae that can symbiotically coexist with indigenous bacteria in actual wastewater attract more significant attention. Ultraviolet (UV) mutagenesis and dissolved organic carbon (DOC) acclimation were applied to strengthen the carbon-fixing performance of microalgae in this study. The mechanisms associated with microalgal water purification ability, gene regulation at the molecular level and photosynthetic potential under different trophic modes resulting from carbon fixation and transformation were disclosed. The superior performance of Chlorella sp. MHQ2 was eventually screened out among a large number of mutants generated from 3 wild-type Chlorella strains. Results indicated that the dry cell weight of the optimal species Chlorella sp. HQ mutant MHQ2 was 1.91 times that of the wild strain in the pure algal system, more carbon from municipal wastewater (MW) were transferred to the microalgae and re-entered into the biological cycle through resource utilization. In addition, COD, NH3-N and TP removal efficiencies of MW by Chlorella sp. MHQ2 were found to increase to 95.8% (1.1-times), 96.4% (1.4-times), and 92.9% (1.2-times), respectively, under the extra DOC supply and the assistance of indigenous bacteria in the MW. In the transcriptome analysis of the logarithmic phase, the glycolytic pathway was inhibited, and the pentose phosphate pathway was mainly carried out for microalgal life activities, further promoting efficient energy utilization. Upon analysis of carbon capture capacity and photosynthetic potential in trophic mode, the addition of NaHCO3 increased the photosynthetic rate of Chlorella sp. MHQ2 in mixotrophy whereas it was attenuated in autotrophy. This study could provide a new perspective for the study of resource utilization and microalgae carbon- fixing mechanisms in the actual wastewater treatment process.

Synthesis and characterization of a β-cyclodextrin-MOF-based porous hydrogel for efficient adsorption of Au3+, Ag+, and Pb2+ ions

Wastewater containing heavy metal ions produced by electroplating, smelting and other industries poses a threat to human safety. Recently, metal–organic frameworks (MOFs) have emerged as porous crystalline adsorbents for the removal of heavy metal ions. Starch-derived cyclodextrins (CDs), a series of cyclic oligosaccharides, have been explored for fabrication of cost-efficient MOF materials. However, the coordination bonds in CD-based MOFs can be destroyed by water, which limits their application as absorbent materials for the removal of heavy metal ions from wastewater. In this work, a β-CD-MOF-based porous hydrogel was developed by incorporating a crosslinked hydrogel network based on acrylic acid (AA) and N,N’-methylenebis(acrylamide) (MBA) monomers into a β-CD-based MOF structure. The synthesized porous hydrogel, denoted A/M−CDMOF−gel, not only showed enhanced structural stability but also exhibited excellent properties for simultaneous adsorption of Au3+, Ag+, and Pb2+ ions. A kinetic study revealed that the A/M−CDMOF−gel had a satisfactory binding rate within 60 min of contact, and the higher fit coefficient from the pseudo-second-order model indicated its chemical adsorption property. Moreover, according to the Langmuir isotherm model fitting results, the maximum capacity of the A/M−CDMOF−gel reached 316.4, 60.9, and 414.2 mg/g for Au3+, Ag+, and Pb2+, respectively. Therefore, the regenerable A/M−CDMOF−gel adsorbent is expected to provide ideas for the development of renewable absorbent materials in the field of wastewater treatment and remediation.

Electron beam radiation coupled to flocculation for advanced treatment of coking and dyeing wastewater: Performance and synergistic effect

Advanced treatment of industrial wastewater is a tough problem in the field of wastewater treatment. In this study, the electron beam radiation coupled to flocculation process was firstly developed and investigated for the advanced treatment of coking and dyeing wastewater. Three different coupled processes were studied, i.e. electron beam radiation followed by flocculation process (EBF), flocculation followed by electron beam radiation process (FEB), and simultaneous electron beam radiation and flocculation process (SEBF). It was found that different processes had various performances in the removal of targeted organic pollutants. For humic acid, FEB with poly aluminum ferric chloride (PAFC) as flocculants showed the best synergistic effect at 10 kGy, in which the removal of humic acid was 95.2%, while SEBF exhibited the inhibition effect under all the conditions. For Rhodamine B, EBF with PAFC had the highest synergistic effect at 10 kGy, in which the removal of Rhodamine B was 87.4%. For phenol, SEBF with PAFC as flocculants showed the highest synergistic effect at 10 kGy, in which the phenol removal was 64.2%. The transformation of organic pollutants, such as the polymerization was the main reason for the synergistic effect of EBF, while the dissolved iron ions and the enhanced oxidation made major contribution to the synergistic effect of FEB, and the structural change of flocculants and the transformation of organic pollutants during the process of electron beam radiation was mainly responsible for the synergistic effect of SEBF. EBF showed better performance in COD removal for actual coking and dyeing wastewater than FEB, indicating that electron beam radiation could promote the flocculation effect. Considering the operation procedure and treatment cost comprehensively, EBF with PAFC is recommended for the advanced treatment of actual coking and dyeing wastewater. This study could provide a novel and effective method for the advanced treatment of industrial wastewater.

Construction of S scheme ZnO/g-C3N4 heterojunction for the removal of pyridine from coal chemical wastewater

In order to achieve the removal of nitrogen-containing heterocyclic compound pyridine in coal chemical wastewater. The S scheme ZnO/g-C3N4 heterojunction was constructed by evaporation solvent-high temperature thermal polymerization. The construction of the S scheme heterojunction effectively improved the photocatalytic activity. The S scheme heterojunction well retained the h+ with high oxidation activity of ZnO-VB and the e− with high reduction activity of g–C3N4–CB, achieving efficient separation of e−-h+. The complex band structure and potential difference lead to the bending of the band and the formation of the internal electric field, which effectively realizes the charge separation. ZnO/g-C3N4 heterojunction shows good activity and stability, and has great potential in the field of organic pollutant wastewater treatment. The construction of S scheme heterojunction also provides a new way to improve the activity of photocatalyst.

Evaluation of operational efficiency and performance for a water treatment plant

The current study presents a comprehensive analysis of the operational efficiency and performance evaluation of the Hazelmere Water Treatment Plant over the period from 1999 to 2018. By focusing on the removal efficiencies of few parameters including iron (Fe), turbidity, and E. coli, the study provides valuable insights into the plant's ability to treat water effectively and produce high-quality drinking water. Leveraging data analysis techniques and computational tools, the research also explores the forecasting of water quality parameters beyond the study period, enhancing predictive capabilities for monitoring and managing water quality in the future. The Hazelmere Water Treatment Plant (WTP) has a daily capacity of 75 Ml it supplies water to the surroundings. Its intricate treatment process, featuring chemical dosing, clarification, filtration, and disinfection, operates harmoniously. The plant consistently exceeded global standards. Effluent turbidity consistently met stringent World Health Organization/South African National (WHO/SANS) discharge standards at ≤ 1 NTU. The turbidity removal efficiencies ranged from 65.88 to 99.61 % on average over the period from 1999 to 2018. Iron removal also adhered to WHO/SANS criteria, registering ≤ 2 mg/L. The removal efficiencies have ranged from 82 to 99% on average for the same period. Most impressively, E. coli removal efficiency maintained a flawless 100 % for the same period, indicating a pathogen-free effluent throughout the period, with a steady annual average of 0 MPN/100 m, some challenges have occurred including the contamination of the freshwater from the dam, the limited data availability, and issues related to sustainability and compliance. These challenges were overcome by using advanced tools for data analyses such as R package, developing a performance evaluation framework and establishing recommendations for the adoption of innovative technologies, and improvements in operation and maintenance practices. Overall, this study makes significant contributions to the field of wastewater treatment and water quality management, advancing our understanding of sustainable water resource management and environmental protection.

A novel magnetic Fe, N co-doped Ce-MOFs derived carbon as a peroxymonosulfate activator for the degradation of tetracycline hydrochloride: Performance and activation mechanism

The activation of peroxymonosulfate (PMS) using metal-organic frameworks (MOFs) has garnered significant interest in the field of wastewater treatment. However, the environmental challenges associated with traditional methods for synthesizing MOFs precursors, such as the requirement for high temperatures and pressures, remain. Furthermore, the catalytic performance and stability of mono-metallic materials are areas needing enhancement. This work successfully synthesized a novel magnetic Fe-Ce bimetallic N-doped porous MOF material (Fe/Ce@5MNC). The optimized Fe/Ce@5MNC exhibited a higher specific surface area and a more extensive pore structure, as verified by various characterization techniques. Moreover, the synthesis process of the precursor is simpler, energy-saving, and relatively environmentally friendly. Notably, the synergistic effect between Fe and Ce, coupled with the presence of multiple active sites such as FeNx and graphite N, enabled Fe/Ce@5MNC to decompose 86.4 % of TCH within 30 min, marking a 31.4 % increase over Ce@NC. After four cycles, the catalyst maintained good surface stability, with the degradation efficiency remaining at 67.7 %. Quenching and electron paramagnetic resonance (EPR) experiments confirmed that the main degradation mechanisms are singlet oxygen (1O2) generation and electron transfer. This study presents a new method for synthesizing efficient Fe, N co-doped magnetic bimetallic PMS activators and designing carbon catalysts for deep oxidation.

Optimal cross-linking of MXene-based membranes for high rejection and low adsorption with long-term stability for water treatment

The unique layered structure and abundant 2D nanochannels of MXene membranes have demonstrated outstanding permeability, indicating their great potential in the field of water treatment. However, their unstable interlayer spacing and irregular layer structure have limited their ability to separate small molecular pollutants effectively. In this study, we successfully prepared composite MXene membranes with high rejection and low adsorption properties by exploiting the differences in the surface functional groups and chain lengths of dopamine (DA) and polyethylene glycol (PEG) through an optimal cross-linking approach. These composite membranes exhibited excellent stability in terms of interlayer spacing and mitigated the adverse effects of stacking defects. Compared to MXene membranes, the composite membranes achieved a 1.76-fold increase in dye rejection efficiency, reaching 98.7% at most, with an adsorption ratio of only 1.8%. Moreover, outstanding performances were also exhibited in pressure and concentration load tests. Furthermore, in the context of forward osmosis applications, the composite membranes demonstrated excellent Na+ rejection of 99.9%. More importantly, these membranes showed no performance deterioration throughout 50 filtration cycles, with only a slight increase in permeance of 19.3% over a 38-day testing period. Thus, this work presents a novel solution for fabricating MXene composite membranes with low swelling, minimal defects, and high stability, enhancing its potential in the field of water and wastewater treatment.

Ultrafast dyeing wastewater purification by high-performance and reusable lignin-derived activated porous carbon filter

Achieving ultrafast purification during filtration while maintaining high adsorption capacity and low-cost filter production is a critical challenge that must be addressed immediately to promote large-scale water filter applications, particularly in remote areas without wastewater purification plants. Herein, low-cost, renewable lignin was used as a carbon source precursor to produce a high-performance, reusable activated porous carbon filter for ultrafast dye wastewater purification. Lignin-derived active porous carbon (LAPC) can achieve a high specific surface area (2276 m2/g) by using a lower amount of KOH (a mass ratio of 0.4 KOH to precursor) during the activation process, which not only meets the requirements of water transport and dye adsorption, but also reduces manufacturing costs. Owing to the pore-filling effect and electrostatic interaction, the LAPC particles displayed a high removal capacity of 1800 mg/g in the static adsorption, higher than most of the reported porous carbon. Furthermore, LAPC filters assembled from a flow of LAPC particles achieve significant dye removal (99.82 % in 30 s) during the dynamic adsorption process. Both anionic and cationic dyes can be removed and clean water can be produced simultaneously by simple dynamic filtration. Moreover, the LAPC filter could be reused for wastewater purification with a high removal efficiency (more than 95 % after 7 cycles of regeneration and use). This continuous operation, strong absorption versatility, and high efficiency of LAPC filter device for complex hybrid dyes system make it have a bright prospect in industrial dyeing wastewater treatment fields.

Chinese yam-derived aerogel as a versatile platform for efficient freshwater production and pollution remediation

Water scarcity and pollution have become major obstacles to sustainable global development. The development of a versatile platform that can simultaneously produce clean water and remediate pollutants from water is highly desirable but still difficult to realize. Herein, to address this challenge, we have developed a CY@PPy@Ag aerogel with excellent photothermal and photocatalytic capabilities through a freeze-drying process, followed by polypyrrole coating and Ag deposition. The excellent characteristics, including broad-spectrum light absorption (97.2%), localization of converted heat, rapid water transport, and porous open microchannels, enabled it to act as an advanced solar evaporator for efficient and continuous steam generation without salt crystallization. Moreover, the high evaporation rate (1.51 kg m−2 h−1) was maintained even in high concentrations of brine and real seawater. Taking advantage of its enhanced photocatalytic performance, organic dyes in water could be rapidly and completely decomposed by the CY@PPy@Ag aerogel under solar irradiation, and this photodegradation process was significantly accelerated with the help of NaBH4. This work is expected to provide a one-stone-two-birds strategy to simultaneously achieve clean water harvesting and pollution remediation, which holds great promise in the fields of solar energy harvesting, wastewater treatment, and seawater desalination.

Phase engineering induces electron redistribution to turn periodate activation activity of MoS2

MoS2-based materials are promising in the field of wastewater treatment. However, the potential application and intrinsic mechanism of MoS2-driven periodate (PI) remains unclear. Here, the MoS2 materials with different 1T/2H ratios, which were characterized by XRD, Raman and XPS were synthesized. The MoS2/PI system could signally promote oxytetracycline (OTC) degradation under dark conditions and 1T/2H ratio of MoS2 has a noticeable effect on the catalytic performance. Specially, the kobs of L-1T-MoS2 (50% 1T phase) was 1.59 and 3.62 times of H-1T-MoS2 (∼74% 1T phase) and 2H-MoS2 (100% 2H phase). The results of quenching experiments, EPR, EIS, I-t and Tafel polarization curves showed that •OH and 1O2, rather than O2•−, H2O2, IO3•, high-valent oxide oxidation and electron transfer, played important roles in MoS2/PI systems. XPS analysis and DFT calculations revealed that Mo was the primary site and phase engineering increased the electron density of Mo sites in MoS2, thereby regulating the activation of PI. These results would enrich understandings on phase engineering of MoS2 to turn its catalytic performance for OTC degradation.

Nano-Fe3O4/polymerize aniline/carbon cathode based microbial fuel cell for efficient power generation and uranium separation

Microbial fuel cells (MFCs) have gained increasing attention in the field of uranium-containing wastewater (UCW) treatment as a self-powered bioelectrochemical system (BES) due to its advantages of recovering uranium resources and generating electricity. However, the lack of catalytic active sites on the carbon fiber cathode significantly hinders the reaction performance of surface electrons with uranium ions in solution, thereby limiting the application of MFC. In this study, we propose a carbon brush (CB) cathode modification process that utilizes cyclic voltammetry synthesis technique (CVS) to polymerize aniline (PA) on the surface of carbon fibers and uniformly load nano-Fe3O4 particles (nFe3O4). The loading of PA/nFe3O4 not only significantly improve the catalytic active sites but also enhance the synergistic effect of adsorption and conductivity of CB cathode. Consequently, the nFe3O4/PA/CB-MFC showed excellent ability to continuous power generation and uranium separation. Over eight cycles of uranium separation, the nFe3O4/PA/CB-MFC exhibited an average maximum power density of 15.17 mW/m2 and a uranium separation efficiency of 95.52 %, showcasing substantial enhancements by 2.10-fold and 1.44-fold compared to the CB-MFC, respectively. Our study presents an efficient approach to enhance the efficiency of uranium separation and boost power density of MFC by increase catalytic active sites on carbon-based cathode.

Using Borax as a Cross-Linking Agent in Poly(Vinyl Alcohol)/Hemp-Extracted Cellulose Hydrogels

This study focused on the preparation of hydrogels of poly (vinyl alcohol) and cellulose extracted from hemp fibers with the aid of borax as a cross-linking agent. Cellulose extracted from hemp fibers was initially dissolved in a mixed solution of urea and NaOH to obtain a cellulose solution. In the meantime, PVA was also dissolved in the urea and NaOH. These two solutions were mixed, and various loadings of borax were introduced. Moreover, the effect of borax loadings on equilibrium water content (EWC) and compression properties of the cross-linked hydrogels was investigated. The cross-linked hydrogels showed an EWC of 95.76% and a compression set of 9.71%, compared to those of the physical cross-linked hydrogels which had an EWC of 92.40% and a compression set of 29.96%. It was found that the chemically crosslinked hydrogels exhibited greater stability compared with physical ones owing to the stronger interaction induced by borax. Therefore, The PVA/cellulose hydrogels cross-linked with borax hold potential in various applications such as wound dressing, wastewater treatment, and agricultural fields.

A green approach to enhance the adsorption capacity: Synthesis of bamboo-based adsorbent by biological pretreatment

Biochar is a low-cost, environmentally friendly adsorbent used in the sewage treatment industry. In most cases, environmentally unfriendly chemical methods are employed when people make attempts to improve its adsorption properties. In this paper, a biological pretreatment method was used to degrade cellulose, which increases the controllable space of pore structure and the specific surface area of the material, thus improving its adsorption performance. Bamboo was first exposed to Trichoderma koningii for three weeks, which was followed by slow pyrolysis to produce biochar. Then, the carbon precursor was crushed and pyrolyzed using KOH to afford an adsorbent. The adsorbent was characterized by multiple approaches, and the adsorption of methylene blue (MB) on it was investigated in detail. In addition, the possible adsorption mechanism was also discussed. Compared with the MB adsorption capacity of the raw bamboo-derived biochar (9.92 mg/g), that of the newly developed adsorbent is enhanced by 25 times (248.57 mg/g), which is benefited from the pretreatment with Trichoderma koningii. And after 5 times of repeated recycling, the removal efficiency of 75.92% could still be maintained. It is expected that bamboo-based adsorbents prepared using Trichoderma koningii-treated bamboo will have a broad application prospect in the field of dye wastewater treatment.

Scientific and technological innovations of wastewater treatment in China

The “dual-carbon” strategy promotes the development of the wastewater treatment sector and is an important tool for leading science and technology innovations. Based on the global climate change and the new policies introduced by China, this paper described the new needs for the development of wastewater treatment science and technology. It offered a retrospective analysis of the historical trajectory of scientific and technological advancements in this field. Utilizing bibliometrics, it delineated the research hotspots within wastewater treatment, notably highlighting materials genomics, artificial intelligence, and synthetic biology. Furthermore, it posited that, in the future, the field of wastewater treatment should follow the paths of technological innovations with multi-dimensional needs, such as carbon reduction, pollution reduction, health, standardisation, and intellectualisation. The purpose of this paper was to provide references and suggestions for scientific and technological innovations in the field of wastewater treatment, and to contribute to the common endeavor of moving toward a Pollution-Free Planet.

Synergistic cobalt‑copper metal-organic framework anchored amino-functionalized cellulose for antibiotic degradation: Interfacial engineering and mechanism insight.

Improving electron transfer rate of Co species and inhibiting aggregation of metal-organic frameworks (MOFs) particles are essential prerequisites for activating advanced oxidation process in wastewater treatment field. Here, we exploit Cu species with variable valence states to accelerate electron transfer of Co species and then to boost the unsatisfactory degradation efficiency for refractory pharmaceuticals via in-situ growth of copper and cobalt species on l-lysine functionalized carboxylated cellulose nanofibers. Utilizing the synergistic interplay of Co sites and deliberately exposed Cu0/Cu1+ atoms, the subtly designed catalyst exhibited a surprising degradation efficiency (~100 %) toward tetracycline hydrochloride within 10 min (corresponding to a catalytic capacity of 267.71 mg/g) without adjusting temperature and pH. Meanwhile, the catalyst displays good recyclability, well tolerance for coexisting ions and excellent antibacterial performance derived from the intrinsic antibacterial property of Cu-MOF. This research provided a novel strategy to construct MOFs-cellulose materials toward degrading various stubborn antibiotic pollutants.

The effectiveness of wastewater treatment of waste treatment facilities of milk processing enterprise and its assessment of by hydrochemical indicators

Despite the attempts made in developed countries to improve production and treatment technology, it has not yet been possible to change the trend of increasing volumes of various wastes. Today, for 5 % of waste there is no effective processing technology at all, and for 60 % it is necessary to organize processing at existing capacities, introducing waste upgrading limits into the process or create new capacities. In this case, waste from one industry will become raw materials or materials for enterprises in other industries. Therefore, today the issue of implementing resource-saving technologies in the field of wastewater treatment from industrial enterprises is relevant. The purpose of the work was to estimate the eff ectiveness of wastewater treatment of waste treatment facilities of milk processing enterprise by hydrochemical indicators. The studies were carried out at treatment facilities into which industrial wastewater from the milk processing enterprise of varying degrees of contamination is constantly discharged. In order to assess the technological effi ciency of the implemented biological treatment system in the filtration fields, wastewater indicators were monitored in the period 2021–2023. It was found that the purification efficiency for some substances has improved. For example, BOD5 from 47,3 % in 2022 to 78,6 % in 2023; ammonium nitrogen from 55,5 % in 2022 to 64,4 % in 2023; chlorides from –12,1 % in 2022 to –0,8 in 2023. However, the results obtained indicate the insuffi cient effi ciency of treatment facilities (filtration fields) and, as a consequence, an unsatisfactory degree of wastewater treatment, which in their turn are a source of pollution of water bodies. Although biological resource-saving treatment systems are the cheapest and most environmentally friendly way to treat wastewater from enterprises, the question of improving such systems remains. This must be done based on the conditions of each specific enterprise.

Magnetic alginate supported potassium manganese ferrocyanide for the recovery of uranium from acidic wastewater

Abstract With the rapid development of the atomic energy industry, the demand for nuclear fuel has risen, while the limited resources of uranium mines make it difficult to meet the needs of the future development of nuclear energy. Expanding sources of uranium acquisition is necessary, and the enrichment and recovery of precious uranium from uranium-containing wastewater is invaluable. By synthesizing alginate supported potassium manganese ferrocyanide nanocomposites with magnetic response (KMnFC/MA/Fe3O4), the high efficiency adsorption and separation of uranium in acidic uranium-containing wastewater can be realized conveniently and quickly. The magnetic composite was characterized by a variety of technical means, and the adsorption behavior of the magnetic material on uranium was studied by static adsorption experiments under different environmental conditions. The adsorption kinetics and isotherm of uranium by KMnFC/MA/Fe3O4 were studied by using some common linear adsorption models. The results show that the adsorption rate of KMnFC/MA/Fe3O4 on uranium is fast, and the adsorption equilibrium can be reached within 90 min. The adsorption process conforms to a pseudo-secondary kinetic model and is dominated by chemisorption. The adsorption of uranium by KMnFC/MA/Fe3O4 magnetic material is single molecular layer adsorption, and the maximum adsorption capacity is 425.5 mg g−1 at 35 °C. KMnFC/MA/Fe3O4 is a promising adsorbent in the field of acidic low-concentration uranium wastewater treatment because of its good effect on the treatment of low concentration uranium wastewater, the concentration of uranium in the wastewater reaches the emission standard after treatment and it is easy to be separated magnetically after adsorption.

One-Step Prepared Multifunctional Polyacrylonitrile/MIL-100(Fe) Membrane with High-Density Porous Fibers for Efficient Dye/Oil Wastewater Remediation.

With environmental pollution becoming more serious, developing efficient treatment technologies for all kinds of organic wastewater has become the focus of current research. In this work, the coaxial electrospinning technology was used to one-step fabricate a porous and underwater superoleophobic polyacrylonitrile nanofibrous membrane with an Fe-based metal-organic framework (MIL-100(Fe)). Benefiting from the synergistic effect of two jets, the nanofibers are smaller and denser, which prompt the exposure of more nanomaterial additives (MIL-100(Fe)). The BET surface area increased to 202.888 m2/g, and the membranes demonstrated outstanding underwater superoleophobicity. Moreover, compared with traditional blended matrix membranes by the single-axis method, separation of the modifier and membrane matrix material by coaxial methods also maintained excellent mechanical properties, which enhanced Young's modulus 3.4 times (∼1.34 MPa). As a result, facing soluble dyes, the porous C-PAN/MIL-100(Fe) membrane can demonstrate outstanding and fast adsorptive property (the Qm of MB and CR reached 44.71 and 88.74 mg g-1, respectively). For oily emulsion, the hydrophilic and oleophobic nanofibrous reticular surface provided excellent separation performance (flux: 1124.0-1549.3 L m-2 h-1, R > 98%). Moreover, the porous and underwater superoleophobic C-PAN/MIL-100(Fe)-0.5 membrane can synchronously purify the dye/oil mixture emulsions by one-step filtration. Based on the above performance, we believe that the modified nanofibrous membrane prepared by one-step coaxial electrospinning technology can promote more studies of the development of membrane preparation technology in the field of oily wastewater treatment.