Problem Of Wastewater Treatment Research Articles

Constructing superhydrophilic/superhydrophobic Janus membrane assisted by dual-interface-confined strategy for on-demand oil-in-water and water-in-oil emulsions separation

Janus membranes with asymmetric wettability have attracted much attention because they can solve the problem that a single wettable material cannot effectively separate complex oil/water emulsions. Here, a dual-interface-confined strategy combining single-side interface-confined floating and single-side interface-confined spraying methods is provided to fabricate a robust Janus membrane with superwettability. The controllable single-side interface-confined floating method introduces a superior stable hydrophobic-superhydrophilic Janus interface, and the single-side interface-confined spraying method guarantees a robust superhydrophobic-superhydrophilic Janus interface. The Janus membrane featured both superhydrophilicity and superhydrophobicity with the outstanding stable interface and remarkable chemical stability could separate not only surfactant-stabilized water-in-oil emulsions by gravity alone, but also handle the surfactant-stabilized oil-in-water emulsions under low separation pressure through simple operation process. Moreover, this superwettable Janus membrane can achieve long-term on-demand oil/water emulsion separation with low flux decline and near 100% flux recovery. Overall, this work develops a new avenue for Janus membrane and provides a new application for a variety of oily wastewater treatment problems.

Enhanced Photodegradation of Methylene Blue Using Reusable Cobalt Ferrite Nanocomposites

Growing industrialization is contributing to the worsening shortage of potable water in society. Consequently, wastewater treatment and dye degradation become the foremost aim to overcome this problem. Magnetic nanoparticles (MNPs) emerged as an efficient tool to overcome the problem of wastewater treatment. Easy recovery of the MNPs reduces the operational cost of the reaction. Therefore, in the current study simple, cheap, green, and highly proficient synthesis methodology for the magnetically recoverable cobalt ferrite is reported. The X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FTIR) confirm the crystalline structure and functional group on the synthesized nanoparticles. The elemental composition, surface morphology, and surface area were investigated by Energy-dispersive X-ray spectroscopy (EDS), Field emission scanning electron microscopy (FESEM), and Brunauer-Emmett-Teller (BET) analysis. The Photo-Fenton process was used to check the catalytic activity of the prepared CoFe2O4 nanoparticles (NPs). The effect of the various experimental parameters like pH (3–9), catalyst dosage (50–200 mg/L), H2O2 dosage (5–20 mM), and varied dye (methylene blue) concentration (0.05–0.2 mM) on catalytic performance were studied. According to this investigation, 90% degradation of the methylene blue was achieved in just 90 minutes using the assynthesized catalyst. The catalyst showed 76.91% of the dye degradation even after 4 consecutive cycles; it suggests the admirable stability of the catalyst during the reaction. The robustness of the CoFe2O4 NPs makes it potential candidate for the waste water treatment.

Sustainable sewage water treatment based on natural plant coagulant: Moringa oleifera

In response to global water scarcity and environmental degradation, one promising technique in natural plant coagulation that has gained attention in recent years is the use of Moringa oleifera a plant native to the Indian subcontinent. This study investigates the potential of Moringa oleifera as a sustainable solution for sewage water treatment. The problem of effective wastewater treatment was addressed by employing Moringa oleifera as a natural plant coagulant (NPC). The methodology involved the use of a jar test as a qualitative technique in coagulation and flocculation to assess the plant’s effectiveness in reducing turbidity and impurities in sewage water. The physical and chemical parameters of raw and treated water were analyzed, revealing that an optimum dose of 0.4 g/1000 mL resulted in significant reductions in various water quality parameters: turbidity by 92%, COD by 88%, total solids by 96%, chloride by 75%, total hardness by 74%, and inorganic phosphorous by 68%. The specific reduction in BOD was not provided, indicating a need for further investigation. The results suggest that Moringa oleifera could offer significant improvements in water quality and societal health while promoting sustainability and environmental harmony. The study concludes that Moringa oleifera presents a promising green technique for sustainable sewage water treatment, with implications for future research focusing on the scalability of this method and its effectiveness in treating different types of wastewater.

Optimal control for both forward and backward discrete-time systems

Forward discrete-time systems use past information to update the current state, while backward discrete-time systems use future information to update the current state. This study focuses on optimal control problems within the context of forward and backward discrete-time systems. We begin by investigating a general optimal control problem for both forward and backward discrete-time systems. Leveraging the inherent properties of these systems and the Bellman optimality principle, we derive recursive equations as a means to solve such optimal control problems. Using these recursive equations, we obtain analytical expressions for both the optimal controls and optimal values of bang–bang and linear quadratic optimal control problems. Finally, we present a numerical example and an industrial wastewater treatment problem to illustrate and demonstrate our findings.

Study on the preparation and performance of PVDF/SMA/CdS Fenton-like membrane with both separation and dye degradation functions

Nowadays, the discharge of wastewater causes serious environmental pollution, affecting the living environment and the health of human beings. So the problem of wastewater treatment is imminent. In this context, the PVDF/SMA/CdS membranes had oil-water separation and dye degradation effects were prepared by using non-solvent phase transition and in-situ deposition methods. Its separation efficiency reached more than 98%, and the oil-water removal rate was at more than 90% after 5 times of recycling. Under visible light irradiation, it could completely degrade methylene blue solution (MB, 10 mg·L-1, pH=3) within 20 min, cochineal solution (Ponceau 4R) within 12 min, and chromium blue-black R (EBR) solution within 6 min, and the degradation rate was at more than 95% after 5 cycles. Therefore, the PVDF/SMA/CdS membrane can effectively treat wastewater. This study opens up a promising avenue for wastewater treatment technology with high potential for application.

In-situ hydrothermal synthesis of MoS2 /TiO2 nanocomposites for enhanced and stable photocatalytic performance: Methylene blue degradation pathway and mechanism

BackgroundIn recent years, nanocomposite photocatalytic has become more and more attractive and important since it has a great potential to contribute to such wastewater treatment and environmental problems. Pollutant dyes such as methylene blue (MB) have utilizations in manufacturing, paper, medicine and textiles. In addition, creating a Z-scheme nanocomposite illustrates a fitting approach for improving the photocatalytic performance of photocatalysts. Mott-Schottky curves demonstrate that MoS2 and TiO2 are combined to form Z-scheme nanocomposite. MethodsNovel MoS2/TiO2 nanocomposite photocatalysts were well synthesized by a simple hydrothermal process. The photodegradation intermediate products of MB dye are also identified by liquid chromatography-mass spectrometry (LC-MS) and the possible degradation pathway is proposed. Ultimately, the potential photocatalytic pathway mechanism of nanocomposites was verified according to the LC-MS analysis and trapping experiments. Significant findingsThe construction of a Z-scheme nanocomposite is a crucial factor in improving the photocatalytic activity of heterojunction photocatalysts. MoS2/TiO2 nanocomposites had photocatalytic activity within 120 min irradiation to visible light and achieved 98.5 % of MB. A stable heterostructure has been effort designed using MoS2/TiO2 with improved electron and hole migration. The photodegradation performance for MoS2/TiO2 is 3.8 folds that the bare photocatalysts. This nano-heterojunction significantly suppresses the recombination rate of photoexcited charge carriers and enhances the operation of solar energy. The Z-scheme nano-heterojunctions offer a potential strategy for promoting the utilization of photocatalysts in waste environmental purification and clean water.

G-C3N4 modified with non-precious metal Al with LSPR as an efficient visible light catalyst.

The issue of water pollution has emerged as a formidable challenge, prompting a pressing need for solutions. The utilization of metal nanoparticles with surface plasmon resonance and semiconductor composite photocatalysts is regarded as a highly effective approach to solve this problem. g-C3N4 is an effective catalyst for the degradation of organic pollutants. Its photocatalytic performance is usually enhanced by the use of the noble metal Au Ag. However, the high cost of these materials limits their application. In this study, we present the synthesis of Al NPs/g-C3N4 nanocomposites using the bridging effect of ligands. The characterized of transmission electron microscopy (TEM), X-ray diffractometer (XRD) and ultraviolet-visible spectroscopy (UV-Vis) proved that Al NPs/g-C3N4 with a wider light absorption range were successfully synthesized. The effects of ligands, (glutathione (GSH), glutamic acid (GAG), and cysteine (CYS)), Al diameter (40 to 200 nm) and the ratio of Al to g-C3N4 (1:1 to 5:1) on the photocatalytic degradation of methylene blue (MB) by Al NPs/g-C3N4 were also evaluated. The results showed that the optimum degradation efficiency of Al NPs/g-C3N4 for MB at 5 mg/L reached 100% within 60 min, which was 11 times higher than that of pure g-C3N4. The principal analysis of Al enhancing the photocatalytic performance of g-C3N4 was studied through transient photocurrent spectroscopy (TPC), electrochemical impedance spectroscopy (EIS), and steady-state transient fluorescence spectroscopy (PL). The results confirmed that hot carriers generated by localized surface plasmon resonance (LSPR) of Al nanoparticles increase the carrier concentration. In addition, the Schottky barrier generated by Al and g-C3N4 could also improve the carrier separation rate and increase the carrier lifetime. This work is expected to solve the problem of organic wastewater treatment and lay the foundation for subsequent research on photocatalysis.

Sustainable Water Management: An Integrated Approach to Solving the Problems of Wastewater Treatment

The relevance of the study of this problem today lies in the fact that the awareness of the lack of water resources and the threat of environmental pollution forces us to focus on the development of sustainable water management solutions. In the context of population growth, water pollution and climate change, it is necessary to respond quickly and improve wastewater treatment methods, assess their impact on the environment and improve water supply systems to ensure stable and environmentally safe access to water resources for future generations. The purpose of this article is to consider an integrated approach to solving the problems of wastewater treatment, assessing their impact on the environment, and improving the water supply system to build a sustainable water economy. Among the methods used, it should be noted the analytical method, the classification method, the functional method, the statistical method, the synthesis method, and others. Water management and environmental protection research included analysis of wastewater treatment technologies, environmental impact assessment, development of water supply systems, municipal waste management, hydrological processes, environmental pollution, use of renewable energy, risk assessment and soil erosion. The effectiveness of wastewater treatment systems, the need for technology improvement, the impact of some types of industry and agricultural activity on the environment, the need to modernize water supply systems, effective management of urban waste, conservation of water resources and prevention of soil erosion were revealed. Research results indicate the need to develop strategies and policies to preserve water resources and improve the state of the environment. This research makes a significant contribution to science, contributing to the development of sustainable water management by developing an integrated approach to solving the problems of wastewater treatment, assessing their impact on the environment, and improving the water supply system.

Zn2SnO4/SnO2/g-C3N4 heterojunction: High efficiency photocatalytic degradation of Rhodamine B in simulated visible light

Photocatalysis is an effective solution to wastewater treatment problems, and semiconductor heterojunctions for photocatalysis can effectively separate photogenerated carriers to improve the performance of photocatalytic degradation of pollutants. In this paper, a ternary composite photocatalyst with a heterojunction structure (Zn2SnO4/SnO2/g-C3N4) was prepared to photodegradeRhodamine B in simulated visible light. The experimental findings demonstrate that the Zn2SnO4/SnO2/g-C3N4 photodegradation rates and efficiencies for RhB are much higher than those for SnO2, g-C3N4, SnO2/g-C3N4, and Zn2SnO4/SnO2. We obtained a 3:1 mass ratio of Zn2SnO4/SnO2 to g-C3N4 by optimization, with a maximum degradation rate of 99.5 % and a maximum kinetic constant k of 0.692 min-1·g−1 for the photocatalytic removal of RhB by Zn2SnO4/SnO2/g-C3N4. The radical trapping experiments suggest the primary role of ·O2– for the photocatalytic removal of RhB. The ternary composite photocatalyst Zn2SnO4/SnO2/g-C3N4 shows promise for potential applications in RhB degradation owing to its exceptionally.

UV‐initiated preparation and absorption properties of pseudo‐polyrotaxane cyclodextrin‐based PVA/poly (acrylamide‐co‐acrylic acid) hydrogel

AbstractThe recycling of dyes from dye wastewater is one of the most challenging problems in wastewater treatment. In this study, a pseudo‐polyrotaxane cyclodextrin based PVA/poly (acrylamide‐co‐acrylic acid) hydrogel was prepared by UV‐initiated polymerization. The network structure of the hydrogel and the performance on the dye absorption were adjusted by controlling the content of cyclodextrin. The study was mainly focused on the absorption of methylene blue (MB) in different environments, selectivity of absorption in mixed solutions and the cyclic absorption behavior. At room temperature, the absorption efficiency of this hydrogel for MB and methylene green reached 91.37% and 94.23%, respectively. In addition, the hydrogel exhibited highly selective absorption towards MB in mixed dye solutions. In the absorption‐desorption cyclic experiments, a more cost‐effective and environmental friendly solvent, a mixture of ethanol and water, was used, and after ten cycles, the highest absorption efficiency was basically maintained. Hence, the hydrogel is expected to be a candidate for more efficient and economical absorbent material in dye wastewater treatment.

Study on sewage characteristics in rural China and pollutants removal performance of biologically enhanced internal circulation treatment system

With rapid economic development and urbanization in China, rural wastewater treatment has become an important issue. This study investigated 63 rural sewage treatment stations in northern, central and southern Shaanxi, China for a 1-year period, 2021 to 2022. The main purpose of the research was to investigate the quality and discharge characteristics of rural sewage, along with current problems in rural wastewater treatment, in order to provide evidence for the optimal construction and operation of rural sewage treatment stations. We found that the biodegradability of rural wastewater is adequate, and BOD5/COD ratio in sewage was 0.4, which is suitable for biological treatment. It has obvious intermittent flow cut-off characteristics, and the range of cut-off duration of sewage was 6–16 h/d, which leads to poor pollutant removal efficiency (COD: 50.0 ± 29.2%, NH4+-N: 46.0 ± 26.1%, TN: 38.5 ± 24.9% and TP: 38.3 ± 23.8%) in sewage treatment stations. In response to the above characteristics, the rural sewage biologically enhanced internal circulation treatment (BEICT) system was constructed. After 97 days of operation, the system has a stable removal effect on TN and TP with an average removal rate of 77.42% and 89.69%, respectively, under the condition of influent interruption for 12 h per day. The activated sludge of system maintained good activity and stable sedimentation performance during the whole experiment, with MLVSS/MLSS and SVI of 0.72 and 128 mL/g, respectively. This study can provide the basis and technical support for the accurate design of rural sewage treatment facilities, and has important significance for guiding the treatment of rural domestic sewage in China.

MICROBIAL BIOREMOVAL OF DIVALENT TOXIC METALS

The problems of polymetallic wastewater treatment from mining enterprises as well as the accumulation of organic waste are acute worldwide. The application of any existing methods of wastewater purification is ineffective and impossible due to the huge volumes and high concentrations of metals. Similarly, modern methods are ineffective for the treatment of huge amounts of organic waste. Therefore, there is a necessity to develop novel environmental biotechnologies providing the simultaneous degradation of organic waste and detoxification of toxic metals. The purpose of the work was to theoretically substantiate and experimentally confirm the possibility of toxic divalent cations removal using dissimilatory sulfate reduction via anaerobic fermentation of ecologically hazardous model organic waste. Colorimetric and potentiometric methods were used for pH and redox potential measurement; volumetric and chromatographic methods – to control volume and composition of synthesized gas; permanganate method – to determine the concentration of dissolved organic carbon (DOC); photocolorimetric method via the qualitative reaction with Nessler’s reagent was used to determine the concentration of ammonium ions. The Co2+ and Ni2+ content in medium was determined by a colorimetric method with 4-(2-pyridylazo)resorcinol (PAR). Fermentation parameters were calculated with the use of mathematical and statistical ones. Modified Postgate B medium with different sources of carbon and energy (potatoes, alanine, and meat) was used for cultivation of dissimilatory sulfate reducing bacteria. The anaerobic microbiome obtained from the sludge of methane tanks showed high efficiency to remove Co2+ and Ni2+ from the liquid medium. The highest efficiency (100% in 9 days) was observed when alanine was used as a source of carbon and energy. The slowest metal precipitation process occurred using meat (20 days). Also, the use of a protein substrate did not provide the expected alkalinization of the medium, which could significantly accelerate the process of metal precipitation. The precipitation of cobalt and nickel cations during the hydrogen fermentation of potato starch was complicated by acidification of the medium, but it was equally effective when the pH was adjusted. The proposed approach, the slow dissimilatory sulfate reduction, due to the sparingly soluble calcium sulfate as electron acceptor, can be used as a basis for the development of new biotechnologies for the treatment of wastewater contaminated with divalent heavy metals with the simultaneous treatment of ecologically hazardous compounds.

Green synthesis of graphene-oxide based nanocomposites for efficient removal of methylene blue dye from wastewater

Water-soluble dyes are a common problem in wastewater treatment, requiring highly efficient methods for removal. In this study, novel sustainable adsorbents made from graphene-oxide (GO) and other materials, such as eggshell-derived calcium oxide nanoparticles (CaONPs-ES), fish bone calcium oxide nanoparticles (CaONPs-FB), and durian shell activated carbon (DSAC) were synthesized, characterized, and demonstrated for soluble dye removal from wastewater. Fermented maize grain extract (MES) was used as a green cross-linker in the synthesis process. The resulting nanocomposites, GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC, showed promising adsorption capabilities for methylene blue (MB) dye removal from aqueous environments. The prepared nanocomposites (GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC) were characterize using state-of-art instrumental techniques. The BET measurement revealed that the nanocomposites surface areas were enhanced due to the cross-linking phenomenon, improving their adsorption capability towards MB dye treatment. The adsorption data of GO@CaONPs-FB/DSAC and GO@CaONPs-ES/DSAC was well fitted to the Harkins-Jura and Freundlich models, respectively. The maximum sorption capacities of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC were 1274.5 and 689.7 mg/g, respectively. The MB dye removal mechanism was driven by π-π interaction, hydrogen bonding, electrostatic attraction and physical interactions and the adsorption process of the nanocomposites followed pseudo-second-order kinetics. The adsorptive performance of the nanocomposites was stable, showing ∼96.45 % and ∼85.18 % after 10 successive cycles for GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC respectively. Cost evaluation revealed that bulk synthesis of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC nanocomposites is cost-effective for treating large quantities of MB contaminated water and other potential dyes as well. Finally, the independent and synergetic contributions between pH, adsorbent dosage and temperature on MB removal by GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC were studied and optimized by central composite design (CCD) an aspect of the response surface methodology (RSM). Finally, this study suggests that the novel green cross-linking approach has a significant impact in enhancing the adsorptive performances of the developed nanocomposites to effectively capture MB from aqueous environment.

Study of the kinetics of the extraction of zinc ions from wastewater by ferritization

Given the relevance of the problem of wastewater treatment from heavy metal ions, and in particular from zinc ions, it is necessary to study the regularities of the process. One of the key aspects is the kinetics of the process and the dependence of the ion extraction efficiency on the duration of the purification process. Reducing the time of the process makes it possible to reduce the cost of electrical energy for technological processes, in particular for the activation of the reaction mixture by heating or electromagnetic pulses.
 Based on the obtained results of the experiment, a mathematical model of the kinetics of the process of extracting zinc ions from wastewater by ferritization with thermal and electromagnetic pulse activation was built. A regression model was used for data processing and an algorithm for calculating the dependence of the degree of purification on the time of the process was proposed. Determined the degree of purification of wastewater from heavy metal ions at different values ​​of the process duration. The expediency of carrying out the process of ferritization cleaning with a duration of 10-15 minutes has been substantiated.

Ce‐Doped MoO3 Photocatalyst as an Environmental Purifier for Removal of Noxious Rhodamine B Organic Pollutant in Wastewater

Wastewater treatment and management have been hot topics for the past three decades. Water reuse can help to alleviate the problems of water shortage and wastewater treatment in practice. Water can be used for household uses once the organic contaminants are removed. In this research, bare MoO3 and Ce‐doped MoO3 are fabricated using a straightforward hydrothermal method for wastewater treatment. The different analytical techniques are utilized to study the physiochemical features of all the synthesized products. Rhodamine B (RhB) is reduced photocatalytically under exposure of visible light to ascertain the possible capacity. The photocatalytic results suggest that the photoreduction of RhB with 2% Ce‐doped MoO3 exhibits a greater photocatalytic activity of 91.83% than the pure and other doped materials. The kinetic study of 2% Ce‐doped MoO3 displays the greater rate constant of 0.0163 min−1 and a lower Rct value of 0.95 Ω. The research indicates that the doping approach is a very effective way to decrease the bandgap and boost RhB's photocatalytic reduction. Other environmental and water‐related problems can be solved using Ce‐doped MoO3's improved physical and structural characteristics.

Scalability of the multi-anode plug flow microbial fuel cell as a sustainable prospect for large-scale design

Designing scalable and cost-effective microbial fuel cells for practical applications is a problem in wastewater treatment. The performance and scalability of the new multi-anode plug flow MFC (MAPF-MFC) with a shared cathode, in three different scales or anodic configurations (C1, C3, and C6) and at three different flow rates, Q (Q1: 15.33 mL/min, Q2: 46 mL/min, and Q3: 76.66 mL/min) were evaluated. The results revealed a consecutive increase in power density, energy recovery, organic removal rate, and a decrease in internal resistance scaling up. The MAPF-MFC configuration C6 (57.59 mW/cm2) produced 6.9-times and 27.9-times that of C3 and C1 in power density, and 1.6-times and 3.5-times in CE with 38.2%, that of C3 and C1, respectively. C6 (45.8 gCOD/L/day) was also 24.8-times and 48-times that of C3 and C1, and 1.5-times to 1.8-times higher in continuous current generation. C1, however, achieved 82% COD removal efficiency, 1.05-times and 1.3-times that of C3 and C6, respectively. A cost-benefit analysis of the configurations revealed a potential annual power output of $28,048.9/a by C6 and a 0.062 cost-benefit ratio. The study demonstrated the MAPF-MFC's capacity to significantly improve power production, energy recovery, and wastewater treatment while scaling up MFCs at a high economic potential.

Construction of novel type II heterojunction WO3/Bi2WO6 and Z-scheme heterojunction CdS/Bi2WO6 photocatalysts with significantly enhanced photocatalytic activity for the degradation of rhodamine B and reduction of Cr(VI)

As a novel photocatalyst with visible light responsiveness, Bi2WO6 has excellent activity in treating wastewater containing organic pollutants and noble metals. However, its photocatalytic action is limited due to the rapid recombination of photogenerated electrons and holes. Based on the study of Bi2WO6, a type Ⅱ heterojunction photocatalyst (WO3/Bi2WO6) and a Z-scheme heterojunction photocatalyst (CdS/Bi2WO6) were constructed. Composites exhibited higher catalytic activity than pure Bi2WO6. The degradation efficiency of RhB(50 mg/L) and reduction efficiency of Cr(VI) (50 mg/L) by 5%WO3/Bi2WO6 catalyst within 60 min of photocatalytic reaction was 98.82% and 53.82%, respectively. The degradation efficiency of RhB and reduction efficiency of Cr(VI) by 15%CdS/Bi2WO6 catalyst was 99.52% and 69.52%, respectively. By studying the structural composition, microscopic morphology, photoelectrochemical performance, and light absorption performance of the catalysts of the two different systems. These mechanisms may help to explain the reasons for the enhanced activity of the composite photocatalysts. In addition, mixed wastewater containing organic pollutants (RhB) and heavy metal ions (Cr(VI)) was used to simulate real and complex wastewater, which provided more ideas for wastewater treatment problems.

Technologies Based on Phototrophic Microorganisms As a Promising Way to Achieve Carbon Neutrality in Urban Agglomerations

Today, a significant part of the world’s population lives in urban agglomerations. A high building density, a large number of vehicles, and industrial enterprises negatively affect both the air quality in the city itself and the climate in general, releasing a significant amount of carbon dioxide. In this regard, there is a need not only to revise the structure of urban developments and strategies for their greening, but also to propose new technologies that radically change the ecological situation. In this paper, solutions using phototrophic microorganisms are considered as such a technology. It is shown that photobioreactors for their cultivation can be successfully integrated into urban systems, while in addition to air purification, the problem of surface wastewater treatment for their further use can also be solved. A wide range of products obtained from the biomass of phototrophic microorganisms significantly increases the economic attractiveness of this approach. Modern technologies in the field of the Internet of Things make it possible to successfully integrate photobioreactors into the urban digital environment.

Functional cellulose aerogel nanocomposites with enhanced adsorption capability and excellent photocatalytic performance

A novel functional cellulose carbon aerogel@Na2Ti3O7@Cu2O (CA@Na2Ti3O7@Cu2O) nanocomposite was prepared by in situ growth technique and impregnation method, and its photocatalytic and adsorption properties were explored. The cationic intercalation structure of Na2Ti3O7 nanosheets gives CA@Na2Ti3O7@Cu2O nanocomposites excellent adsorption capacity of heavy metal ions (31.0–118.7 mg/g). The Cu2O nanoparticles in CA@Na2Ti3O7@Cu2O nanocomposite showed excellent photocatalytic activity, and the removal rate of methylene blue (MB) was up to 99 %. Furthermore, the CA@Na2Ti3O7@Cu2O nanocomposites could be easily regenerated and reused, providing a new way to effectively solve the problem of wastewater treatment containing heavy metal ions and organic dyes.

Activation of bentonite and palygorskite adsorbents by acid under microwave radiation

The problem of wastewater treatment, since the second half of the 20th century, is relevant for all countries of the world. There are quite a few purification methods, however, adsorption methods are simple and effective methods of water purification. The advantages of these methods are high efficiency, the possibility of treating wastewater containing several substances, as well as the recovery of these substances. Active carbons, synthetic sorbents and some production wastes (ash, slag, flask, sawdust), mineral sorbents - clays, silica gels, alumogels and metal hydroxides are used as sorbents. The research illustrates the possibility of acid activation of bentonite and palygorskite clays using microwave radiation. It has been established that the microwave activation of bentonite leads to the destruction of the structure, the expansion of the surface and the change in the pore structure, which affects the textural characteristics. The concentration values of hydroxyl groups indicate the presence of surface active sites that can participate in adsorption. The results were presented as tables and as a graph.