Removal Of Pollutants Research Articles

Green synthesis of ZnO and Ni-doped ZnO from okra stalks for the photocatalytic degradation of Procion Red MX-5B

This study investigates the photocatalytic degradation of Procion Red MX-5B (PRM) using ZnO and Ni-doped ZnO catalysts derived from okra stalks through a green synthesis method. Various parameters, including hydrogen peroxide concentration (HPC), catalyst amount, nickel (Ni) doping amount, initial PRM concentration, and pH, are systematically studied to assess their impact on PRM degradation efficiency. The results reveal that both ZnO and Ni-doped ZnO catalysts exhibit promising photocatalytic activity, with the highest PRM degradation efficiency achieved at the following reaction conditions: 6 mM of HPC, 40 mg of Ni(7%):ZnO catalyst, 10 ppm initial PRM concentration, and pH = 6. Under these conditions, the Ni-doped ZnO catalyst demonstrated a degradation efficiency of 98.08% compared to 82.99% for the ZnO catalyst. The study highlights the potential of these catalysts for efficient organic pollutant removal and provides valuable insights into the factors influencing their photocatalytic performance.

Physical modeling of organics-contaminated groundwater remediation by ozone micro-nano-bubbles enhanced oxidation

Ozone micro-nano-bubbles (MNBs) enhanced oxidation is a promising in-situ remediation technology for organics-contaminated groundwater. The transport behavior of MNBs and contaminant removal effect in actual groundwater scene is not yet comprehensively understood, although one-dimensional column experiments and batch tests were conducted to investigate the migration of MNBs and contaminant degradation in previous studies. Here, a novel two-dimensional (2D) physical modeling facility was developed, which can characterize the tempo-spatial distribution of MNBs and contaminant in groundwater. The facility was used to explore the migration of MNBs under different hydraulic gradients and the removal of methyl orange, a representative organic pollutant, using ozone MNBs. The experimental results show that groundwater flow velocity has a significant influence on the migration behavior of MNBs. A model including groundwater flow, MNBs transport, and dissolved gas transport can well capture the migration and distribution of MNBs under different hydraulic gradients. The longitudinal and transverse dispersivities of the MNBs were calculated to be 1.14 cm and 0.18 cm, respectively. MNBs are able to migrate with groundwater flow to long distances and exhibit strong dispersion in the lateral and longitudinal directions. The increase in hydraulic gradient greatly enhances the transport of MNBs in groundwater and relieves the deposited MNBs on the surface of porous media. At a hydraulic gradient increasing from 0.033 to 0.1, the range of influence of MNBs increased from about 80 cm × 40 cm to 140 cm × 39 cm after 36 h of injection of oxygen MNBs water. The methyl orange in groundwater is effectively removed by ozone MNBs enhanced oxidation, showing the remarkable remediation ability of ozone MNBs. The area of influence and pollutant removal of the ozone MNBs expanded with injection, and the area of influence was approximately 48 cm × 30 cm after 48 h of treatment. We also discuss the effect of groundwater matrix on ozone MNB migration and degradation of contaminants. The 2D model tests illustrate the mechanism of MNB migration and indicate that ozone MNBs enhanced oxidation technology has great potential in the remediation of organics-contaminated groundwater.

Enhanced photocatalytic properties of visible light-responsive ZnS/FeWO4 composites for degradation of tetracycline and Escherichia coli inactivation

The development of highly efficient visible light-driven photocatalysts for the removal of diverse pollutants is crucial for wastewater treatment. In this study, a series of ZnS/FeWO4 composites were prepared via a facile hydrothermal method combined with in situ calcination. The photocatalytic properties of the resulting ZnS/FeWO4 composites were evaluated for the degradation of tetracycline (TC) and the inactivation of Escherichia coli (E. coli), considering the environmental persistence and potential carcinogenicity of these pollutants. The optimized ZnS/FeWO4-1:2 photocatalyst demonstrated outstanding activity in the degradation of TC, achieving a degradation efficiency of 91.7 % (k = 0.0230 min⁻¹), which is significantly higher than that of pristine FeWO4 (67.5 %) and ZnS (53.4 %). Kinetic studies confirmed that the degradation process followed a pseudo-first-order kinetic model. Furthermore, the as-prepared photocatalyst exhibited excellent stability after five cycles. Additionally, the ZnS/FeWO4-1:2 composites showed potent inactivation efficiency, achieving approximately 96 % inactivation of 7.0 × 106 CFU/mL E. coli. These superior photocatalytic capabilities are attributed to the effective integration of FeWO4 with ZnS and the formation of optimal heterojunction structures. This incorporation leads to a delay in electron-hole recombination within the nanocomposites. Moreover, the enhancement mechanisms of photocatalytic TC degradation over ZnS/FeWO4-1:2 composites were discussed. The findings of this study provide valuable insights into the multi-application potential of ZnS/FeWO4-1:2 composites and demonstrate an effective approach to designing photocatalysts for wastewater treatment.

Preparation of artificial humic acid from corn straw and its high-efficiency adsorption on norfloxacin

In this study, the biomass artificial humic acid (AHA) with efficient adsorption performance for norfloxacin (NOR) was prepared by ultrasonic-assisted acid-alkaline combined hydrothermal method with corn straw as raw material. Characterization analysis showed that AHA was a typical amorphous structure, and the oxygen content of AHA prepared by ultrasonic-assisted hydrothermal method was obviously improved compared with that without ultrasonic-assisted method. The saturated adsorption capacity of AHA was 551.53 mg/g, which was higher than that of other reported materials, such high-efficiency adsorption is due to the abundant oxygen-containing groups (–OH, –C=O, etc.) in AHA, which were functional groups that can be π-π stacked, hydrogen bonded and electrostatically bonded with NOR. It had good selective adsorption for NOR, with less interference from acidity of environmental water, coexisting inorganic ions and common antibiotics. When it was applied to adsorb NOR with concentration of 10.0 mg/L in simulated water prepared by environmental water, the highest removal rate was 91%, which indicated that AHA could not only remove all the NOR in the polluted water with complex components at the highest concentration of 630 μg/L, but also its adsorption capacity far exceeded the pollution amount. The research had important practical significance in realizing the recycling of agricultural wastes and the removal of environmental pollution.

Polyethylenimine functionalized graphene oxide and cellulose nanofibril composite hydrogels: Synthesis, characterization and water pollutants adsorption

A stable 2,2,6,6-tetramethylpiperidine-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibril (TCNF)/graphene oxide (GO)/polyethylenimine (PEI) composite hydrogel was synthesized by self-assembly instead of chemical crosslinking. Their chemical, morphology, surface, and mechanical properties were characterized and adsorption behavior for methyl blue (–) was systematically investigated in terms of the optimal GO content, pH effect, kinetics, and isotherm models. Additionally, to assess the adsorption capability of the TCNF/GO/PEI hydrogel for various contaminants, its effectiveness was also tested for methylene blue (+), Cu (II), and soybean oils. The maximum adsorption capability for the methyl blue (−) dyes increased from 3125 to 3962 mg/g when 13.3 % of GO was added. The adsorption capability for Cu (II) and soybean oils rose from 205.3 to 218.5 and 2.1 to 7.2 mg/g, respectively. The adsorption capability of optimized TCNF/GO/PEI hydrogel for a variety of contaminants was improved overall based on the increase of surface area, electrostatic interactions, and hydrophobic domains. Moreover, adding GO did not impact the adsorption mechanism but increased the external diffusion rate in the intraparticle diffusion model. This work provides a self-assembling route to TCNF/GO/PEI hydrogels with great potential for the removal of multiple water pollutants.

Dihydrotetrazine-Functionalized Zirconium-Based Metal-Organic Frameworks for High-Capacity Oil Denitrogenation.

High structural stability, dual organic-inorganic nature, and tunability in chemical functionality are promising characteristics of zirconium-based metal-organic frameworks (Zr-MOFs). These properties assist Zr-MOFs in extending their applications in various fields, especially adsorptive removal of pollutants. In this work, two well-known Zr-MOFs (UiO-66(Zr) and MIL-140(Zr) with the formula Zr6O4(OH)4(BDC)6, H2BDC is benzene 1,4-dicarboxylic acid) were synthesized and decorated with a dihydrotetrazine functional group through postsynthesis linker exchange (PSLE). Two dihydrotetrazine (DHTZ)-functionalized frameworks, UiO-66(Zr)-DHTZ and MIL-140(Zr)-DHTZ, were applied for the removal of quinoline (Qui) and indole (Ind) from the model oil. The results of adsorption experiments at room temperature display that these functionalized Zr-MOFs have significantly improved removal capacities for Qui (875% for UiO-66(Zr)-DHTZ and 303% for MIL-140(Zr)-DHTZ) and Ind (722% for UiO-66(Zr)-DHTZ and 257% for MIL-140(Zr)-DHTZ). Mechanistic studies based on X-ray photoelectron (XPS) and Fourier-transform infrared (FT-IR) spectroscopies reveal that there is a specific kind of host-guest interaction between dihydrotetrazine and nitrogen-containing compounds (NCCs). UiO-66(Zr)-DHTZ adsorbs 1426 mg·g-1 Qui and 1176 mg·g-1 Ind, while MIL-140(Zr)-DHTZ adsorbs 619 mg·g-1 Qui and 511 mg·g-1 Ind. The lower adsorption capacities of MIL-140(Zr)-DHTZ compared to UiO-66(Zr)-DHTZ are related to its lower surface area (783 m2·g-1 versus 330 m2·g-1). The recyclability of the frameworks goes up to five cycles without any significant decrease in the removal capacity. These results indicate that dihydrotetrazine-functionalized Zr-MOFs are highly stable platforms with superior adsorption capacity compared to basic and neutral NCCs.

Assessment of carbon efficiency in wastewater treatment plants through Stochastic non-parametric data envelopment analysis (StoNED): Insights from Spanish facilities

Evaluating the carbon efficiency (CE) of wastewater treatment plants (WWTPs) is crucial for guiding these facilities towards carbon neutrality. Nevertheless, enhancing carbon performance ought not to be pursued to the detriment of pollutant removal efficiency. In this study, the CE of WWTPs is calculated as a composite index that integrates carbon emissions with the volume of pollutants removed from wastewater, including organic matter, suspended solids, nitrogen, and phosphorus. To achieve this, the Stochastic Non-parametric Envelopment of Data (StoNED) method is employed. This approach, distinct from the commonly used Data Envelopment Analysis (DEA), accounts for both empirical data and random variations in the estimation of CE, thereby enhancing the reliability of the CE evaluation. The study assesses the CE of 109 Spanish WWTPs, finding that none of them are fully carbon efficient. This involves that all plants have potential to reduce greenhouse gas emissions without sacrificing pollutant removal efficiency. The average CE of the WWTPs is 0.529, indicating a possible reduction in carbon emissions by approximately 0.076 kg of CO2 equivalent per cubic meter of wastewater treated. The analysis also reveals that neither the volume of wastewater treated nor the type of reactor used for secondary treatment has a significant impact on the CE of the facilities. The CE metric proposed in this study serves as an important decision-support tool for advancing towards the carbon neutrality of wastewater treatment processes. By providing a more comprehensive understanding of the environmental performance of WWTPs, it helps identifying areas for improvement and guiding policy and operational decisions.

Enhanced remediation of real agricultural runoff in surface-flow constructed wetlands by coupling composite substrate-packed bio-balls, submerged plants and functional bacteria: Performance and mechanisms

Import of agricultural runoff containing nutrients considerably contributes to eutrophication of receiving water bodies. Surface-flow constructed wetlands (SFCWs) are commonly applied for agricultural runoff purification, but the performance is usually unsatisfactory. In this study, suspended bio-balls filled with zeolite and iron-carbon (Fe-C) composite substrates, submerged macrophyte (Ceratophyllum demersum) and functional denitrifying bacteria were collectively added into SFCW microcosms to enhance the remediation efficiency for real agricultural runoff with high nutrient concentrations and low content of bioavailable organic matter. The bio-ball added SFCWs achieved notably higher pollutant removal efficiencies (21.1%, 80.2% and 47.5% for chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP), respectively) than the control (COD: 6.9%, TN: 64.4%, TP: 27.9%), because of the versatile functions of filling materials for pollutant removal. C. demersum plantation (COD: 44.2%, TN: 82.8% and TP: 53.7%) and functional bacteria inoculation (COD: 51.8%, TN: 85.8% and TP: 55.1%) further enhanced the efficiency of the SFCWs for agricultural runoff remediation. Bio-ball addition and C. demersum plantation significantly increased the humification degree and reduced the molecular weight of dissolved organic matter (DOM) in the agricultural runoff. Moreover, the two intensification measures also notably reduced organic and nitrogen contents in the wetland sediment. Remarkable distinction in bacterial community distribution patterns was observed in the SFCW sediment and filling substrates in bio-balls. Keystone genera including Clostridium_sensu_stricto_1 and Bacillus in the zeolite, Sphingomonas and Exiguobacterium in the Fe-C substrates and Sediminibacterium in the sediment might be critical for agricultural runoff remediation in the SFCW microcosms. The study highlights a high potential of the intensified SFCWs by these coupling measures for agricultural runoff remediation.

The substantial generation of photochemically produced reactive intermediates (PPRIs) in algae-type zones from one large shallow lake promoted the removal of organic pollutants

Photochemically produced reactive intermediates (PPRIs) are ubiquitously present in aquatic systems and hold significant importance in biogeochemical cycles. The photochemical reaction of dissolved organic matter (DOM), known as photosensitizers upon irradiation, is the main pathway for PPRIs generation. However, the PPRIs produced by algal-derived organic matter (ADOM) and their environmental effects remains elusive. This study confirmed that substantial PPRIs were generated by ADOM in the algal-derived areas. UV absorption spectra, fluorescence spectra and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were then indicated a significant correlation between the molecular weight of DOM and the quantum yield of PPRIs, with lower molecular weight of DOM exhibiting a higher potential for PPRIs generation. Orthogonal partial least squares (OPLS) were used to build novel multivariate predictive models for indicating the PPRIs production in algae-type zone. Also, the higher concentrations of PPRIs could significantly removal different kinds of organic pollutants, such as bisphenol A (BPA), sulfadiazine (SDZ) and 17α-ethinylestradiol (EE2). Quenching experiments further elucidated that 3DOM⁎ was the key specie for pollutants degradation, serving as the precursor to generate a series of PPRIs. This study highlighted the importance of PPRIs generated from ADOM in the natural attenuation of pollutants and provided a new insight for understanding the self-purification in aquatic system.

Conservation of Yuan Dynasty Caisson Paintings in the Puzhao Temple, Hancheng, Shaanxi Province, China

Caisson paintings are an integral part of the unique interior decoration ceiling of traditional Chinese architecture. There are a large number of Yuan Dynasty caisson paintings in the Puzhao Temple, in Hancheng, Shaanxi Province, China. These caisson paintings have exquisite patterns and rich colors, which are rare artistic treasures of the Yuan Dynasty. In the history of nearly 700 years, due to various environmental and human factors, the caisson paintings have experienced various degradation; for example, the paper of the caisson paintings is acidified, the surface is polluted, the color is faded, mottled, and it is difficult to identify. Therefore, their protection is vital. In order to ensure the scientific and targeted development of the protection scheme, this study conducted a comprehensive and in-depth analysis of the paper fibers, pigments, adhesives, wood supports, and pollutants of the caisson paintings and carried out a series of protection experiments in the field and laboratory, providing a step-by-step review of the protection treatment application for the caisson paintings. Mechanical and wet cleaning were used to remove the pollutants. The caisson painting was deacidified with a barium hydroxide ethanol solution, and the paper and pigments of the caisson painting were strengthened with water-based fluorine. Several conservation problems, such as the removal of pollutants, the deacidification of acidified paper, and the reinforcement of flaking paper and pigments, were solved. Meanwhile, good conservation and restoration results for caisson paintings were obtained. This research method of combining theory and practice has greatly improved the scientificity and success rate of conservation work. These research results provide valuable experience and reference for other caisson paintings in similar environments.

Exploring non-thermal plasma technology for microalgae removal

The global population and economic development surge has substantially increased water demand, resulting in heightened sewage and pollutant generation, posing environmental hazards. Addressing this challenge necessitates the implementation of efficient and cost-effective water reclamation methods. Non-thermal plasma technology (NTP) has emerged as a promising solution, garnering attention for its superior efficiency compared to alternatives. While existing studies have predominantly focused on energy efficiency and pollutant removal, limited research has delved into the biological removal aspect, particularly concerning algae. This study utilized a dielectric barrier plasma diffuser to eliminate Spirulina microalgae (Spirulina platensis) from wastewater solutions, demonstrating higher algae removal and superior mass transfer compared to alternative plasma methods. The effect of sample volume, input voltage and power, flow rate, and initial solution concentration on the algae removal was investigated. Investigation of operational parameters revealed the best condition resulting in a 98 % removal rate and 20 g/kWh energy efficiency. The best conditions for the removal of Spirulina microalgae were considered in a sample volume of 50 mL, a voltage of 7.6 kV, a flow rate of 700 mL/min, and an initial solution concentration of 1280 mg/liter. Scanning Electron Microscope (SEM) images illustrated the impact of active species on cell structure, leading to the destruction of spiral form and loss of reproductive ability. The study underscores the potential of NTP for efficient algae removal and identifies key active species involved in the process. The removal of Spirulina microalgae was attributed to a combination of singlet oxygen (1O2), hydroxyl radicals, and ozone.

Core-shell nanomaterials based on La2FeCrO6 coated with metal oxides for optical applications

In this research work, the preparation of core/shell nanoparticles comprising La2FeCrO6 (LFCO) as the core was accompanied by the choice of ZnO and CuO as different shells. Structural and optical characteristics were investigated for the LFCO (core) relative to La2FeCrO6/ZnO and La2FeCrO6/CuO core/shell NPs. x-ray diffraction analyses reveal the conformation of core/shell structures within average crystallite sizes of 22.46 nm and 25.03 nm. Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) were performed to provide fundamental information about the vibrational modes and the functional groups of core/shell NPs, respectively. x-ray photoelectron spectroscopy (XPS) detects the electronic states of the constituent elements of the core/shell nanostructures, including lanthanum, iron, chromium, oxygen, zinc, and copper. Optical characteristics have been extensively analyzed using UV spectroscopy. The energy gap (Eg) was determined by utilizing both Tauc and Derivation of Absorbance Spectrum Fitting (DASF) methods. LFCO/ZnO and LFCO/CuO core/shell NPs exhibit a direct optical transition, similar to that of the core LFCO NPs, with a decrease in band gap value from 3.4 eV for the core to 3.3 eV and 3.18 eV for LFCO/ZnO and LFCO/CuO core/shell NPs respectively. The enhanced transparency of core/shell NPs, particularly at longer wavelengths, is evident from the decrease in refractive index (n) compared to that of the core (LFCO) NPs. This decrease is attributed to the encapsulation of LFCO with either ZnO or CuO NPs. The samples exhibit a decline in both linear and non-linear optical susceptibilities with respect to the square of photon energy. The LFCO/CuO sample shows excellent results in the photocatalytic degradation of aqueous organic dyes, considering it a promising candidate for wastewater treatment and the removal of organic pollutants.

High-yield preparation of 1T-MoS2 with excellent piezo-catalytic activity via W6+ doping for antibiotics degradation and Cr(VI) reduction: Mechanistic insights from characterizations to DFT calculations

Molybdenum disulfide (MoS2) is a promising piezoelectric material. Herein, a simple method is reported for the high-yield production of metallic (1 T) phase MoS2 which exhibits excellent piezo-catalytic activity by in-situ doping of trace amounts of W6+. At 1 wt% W6+ doping, the 1 T phase of the obtained MoS2 reaches a concentration as high as 85.56 % and the piezoelectric coefficient and piezoelectric response current increase by 1.67 and 1.18 times, respectively, as compared to pristine MoS2. Consequently, W1.0-MoS2 can remove more than 99.8 % of tetracycline and 97.3 % of Cr(VI) in 10 min. Experimental characterization and theoretical calculations indicate that the enhanced piezoelectric catalytic activity is attributed to the strong synergistic effect between 1T-MoS2 and W6+ doping, which facilitates the rapid generation of hydroxyl radicals and superoxide radicals. This new strategy of doping 1 T/2H-MoS2 with W6+ can significantly enhance the piezoelectric catalytic performance, providing important insights for the removal of pollutants.

Urban wastewater treatment at ambient conditions using microalgae-bacteria consortia in a membrane high-rate algal pond (MHRAP): The effect of hydraulic retention time and influent strength

The effects of hydraulic retention time (HRT) and influent wastewater strength on microalgae-bacteria performance were studied in two sets of experiments in a 6-day biomass retention time membrane high-rate algal pond (MHRAP) pilot plant to assess its pollutants removal potential. In the first set of experiments, the MHRAP was continuously fed with effluent from primary settling and operated at 6-, 4- and 2-days HRT and in the second set, the MHRAP was operated at 4-, 2-, and 1-day HRT using pre-treatment effluent. Results showed a complex interaction between algae-bacteria consortium, ambient conditions and MHRAP operation. In set 1, the highest total nitrogen (T-N) and total phosphorus (T-P) removal efficiencies were reached with 6-day HRT (23.6±0.6 % and 32±4 %, respectively), partially due to free ammonia nitrogen stripping and phosphorus precipitation, because of abiotic factors, which reduces the activity of nitrite-oxidizing bacteria and led to partial-nitrification. On the other hand, the 4 and 2-day HRT T-N and T-P removal efficiencies were reduced (below 10 % and 5 %, respectively) because the abiotic factors limited the physicochemical processes, and less biomass was taken up. In set 2, a suitable equilibrium between the microalgae and bacterial communities at 2-days HRT achieved high T-N (91±5 %) and T-P (71±8 %) removal efficiencies. Mass balances indicated that the nitrogen was mostly removed by nitrification-denitrification (87 % of T-N) and T-P predominant removal mechanism was precipitation. The COD removal efficiencies were higher than 86 % in both sets, since the particulate COD and colloids were removed by ultrafiltration. The obtained results showed that MHRAP technology would allow reducing COD and nutrient loads in the effluent under certain operating conditions, demonstrating the potential for resource recovery and wastewater treatment of microalgae-bacteria consortia.

Multivariate Flexible Metal-Organic Frameworks and Covalent Organic Frameworks.

Precise control of the void environment, achieved through multiple functional groups and enhanced by structural adaptations to guest molecules, stands at the forefront of scientific inquiry. Flexible multivariate open framework materials (OFMs), including covalent organic frameworks and metal-organic frameworks, meet these criteria and are expected to play a crucial role in gas storage and separation, pollutant removal, and catalysis. Nevertheless, there is a notable lack of critical evaluation of achievements in their chemistry and future prospects for their development or implementation. To provide a comprehensive historical context, the initial discussion explores into the realm of "classical" flexible OFMs, where their origin, various modes of flexibility, similarities to proteins, advanced tuning methods, and recent applications are explored. Subsequently, multivariate flexible materials, the methodologies involved in their synthesis, and horizons of their application are focussed. Furthermore, the reader to the concept of spatial distribution is introduced, providing a brief overview of the latest reports that have contributed to its elucidation. In summary, the critical review not only explores the landscape of multivariate flexible materials but also sheds light on the obstacles that the scientific community must overcome to fully unlock the potential of this fascinating field.

Characterization optimization of synthesis Chitosanclay/benzoin/Fe3O4 composite for adsorption of Thionine dye by design expert study

A novel composite material, magnetic chitosan-clay/benzoin/Fe3O4 (CS-CY/Benz/Fe3O4), was synthesized for effectively removing thionine dye (TH) from water solutions. The structural integrity and suitability of CS- CY/Benz/Fe3O4 composite for adsorption purposes were validated through extensive characterization techniques including BET, XRD, FTIR, and SEM. The adsorption efficiency was optimized through a Box–Behnken design (BBD) employing response surface methodology (RSM), focusing on variables such as adsorbent dose (A: 0.02–0.08 g), solution pH (B: 4–10), temperature (C: 30–60 °C), and time (D: 5–30 min). Experimental results revealed a maximum TH removal of 99% with significant interactions between temperature (C) and time (D) (p-value = 0.0001). The optimal conditions for TH removal were determined as pH ~ 5.91, adsorbent dosage of 0.08 g, temperature of 54.34 °C, and time of 29.7 min. The investigation of kinetics revealed that the adsorption process conformed to a pseudo-second-order (PSO) model, while the equilibrium data were effectively described by the Freundlich isotherm model. At a temperature of 333.15 K and a TH concentration of 350 mg/L, the adsorption capacity was determined to be 660.86 mg/g. The mechanism of adsorption encompassed various interactions such as electrostatic attractions, n–π interactions, hydrogen bonding, and Yoshida H-bonding. Particularly, the CS-CY/Benz/Fe3O4 composite demonstrated strong magnetic responsiveness, enabling straightforward separation from water using an external magnetic field after adsorption. Particularly, the CS-CY/Benz/Fe3O4 composite demonstrated strong magnetic responsiveness, enabling straightforward separation from water using an external magnetic field after adsorption. This research contributes important findings to the advancement of magnetic chitosan-based composites for efficient removal of TH dye pollutants from water environments.

Green synthesis of novel Z-scheme SnS2/HAp nanocomposite using Ocimum tenuiflorum leaf extract and investigation of its photocatalytic activity.

The present study focuses on the green synthesis of a novel Z-scheme SnS₂/HAp photocatalyst using Ocimum tenuiflorum (tulsi) leaf extract as a stabilizing agent. This approach not only emphasizes sustainability but also adds value to waste by extracting hydroxyapatite (HAp) from Labeo rohita fish scales, addressing the challenge of their disposal. The synthesized photocatalyst was thoroughly characterized using a range of analytical techniques to evaluate its crystal structure, optical properties, morphology, and elemental composition. The photocatalytic activity of the SnS₂/HAp composite was assessed through the degradation of gentian violet (GV) dye, a representative organic pollutant. Various reaction parameters were optimized to enhance the degradation efficiency, and the photocatalyst's performance was further tested across different water matrices. Under optimal conditions, the SnS₂/HAp photocatalyst achieved a maximum photodegradation efficiency of 97.49% with a rate constant of 0.0494min- 1 for GV dye. Additionally, it exhibited an efficiency greater than 70% against other emerging pollutants via advanced oxidation processes (AOP). The enhanced photocatalytic activity was attributed to the formation of a Z-Scheme heterojunction between SnS2 and HAp, which enhanced the charge separation efficiency and delayed the charge recombination. The study also demonstrated the photocatalyst's remarkable reusability, maintaining high performance over five cycles and across various water environments. This highlights its potential as a sustainable solution for the removal of organic pollutants from aqueous streams. Finally, a Z-scheme electron transport mechanism is proposed to explain the photodegradation process of GV dye using the SnS₂/HAp photocatalyst.

Magnetic PVA/GO-based aerogel for efficient removal of oil pollution

Magnetic PVA/GO-based aerogel for efficient removal of oil pollution

Interface and Defect Engineering in 3D Co3O4‐Ov/TiO2 to Boost Simultaneous Removal of BPA and Cr(VI) upon Photoelectrocatalytic/Peroxymonosulfate (PEC/PMS) System

AbstractThe combination of photoelectrocatalytic (PEC) and peroxymonosulfate (PMS) is an innovative strategy for environmental treatment. And fabricating a highly efficient photoelectrode is the most pivotal factor in PEC reactions. This study designs an advanced Co3O4‐Ov/TiO2 photoelectrode by a dual‐modification strategy encompassing interface engineering and defect engineering. The photoelectric characterization validates the synergy of oxygen vacancies and dual heterojunctions. Simulated electron density distribution and Kelvin probe force microscopy (KPFM) elucidate the charge transfer pathway between Co3O4‐Ov and TiO2. 1O2 and SO4 .− are confirmed to be primarily responsible for the BPA oxidation in PEC/PMS system by radical scavenger experiments and the EPR technique. And the attack sites of BPA are precisely identified based on the Fukui index. Furthermore, density functional theory (DFT) calculations testify that Co3O4‐Ov can improve the adsorption capacity of PMS and reduce the energy barrier of the reaction process, while XPS analysis showed Co3+/Co2+ redox couple can accelerate PMS activation. Enhanced anode oxidation can effectively promote cathode reduction and consequently Co3O4‐Ov/TiO2‐PMS/PEC system presents a superior removal of both pollutants within only 15 min with fast kinetics (0.15 min−1 for BPA, 0.29 min−1 for Cr(VI)). This work provides unique insight into designing a highly efficient PMS/PEC system for simultaneous pollutant treatment.

Tetrabromobisphenol A biotransformation in aged soil: Mechanism analysis induced by root exudates during rhizoremediation of Helianthus annus

Rhizoremediation, recognized as a progressive strategy for the removal of organic pollutants in soil, prominently focused on the influence of root exudates-induced alterations within the rhizosphere on the bioavailability and transformation of pollutants. However, the influence of root exudates on the ultimate fate of tetrabromobisphenol A (TBBPA) in soil remains unclear. The current study embarked on a comprehensive examination of the biotransformation process and underlying mechanisms of TBBPA driven by root exudates of Helianthus annus in rhizospheric soil. The pot experiment underscored the constructive impact of root exudates on enhancing the TBBPA dissipation efficiency within lab-controlled, with the increments of 18.77 %∼38.64 %. The core bacterial players responsible for TBBPA biotransformation were identified, with the prominent genus being Saccharibacteria_genera_incertae_sedis, unclassified_Sphingomonadaceae, and Parcubacteria_genera_incertae_sedis. In rhizospheric soil, a comprehensive analysis disclosed the presence of 20 different biotransformation products of TBBPA. Notably, root exudates were found to predominantly drive the reductive debromination pathway. This study provided for the first concrete evidence that root exudates can promote the desorption of TBBPA from soils. The current study aimed to decipher the molecular mechanisms in biotransformation process of TBBPA mediated by root exudates, and also provided reference for the environmental behavior of organic pollutants induced by root exudates.