Reusability Test Research Articles

Aerobic Oxidation of Vanillyl Alcohol to Vanillin Over CeO2‐Co3O4 Catalyst

AbstractA promising CeO2‐Co3O4 (9 : 1 mole ratio based on oxides) non‐noble metal based mixed oxide catalyst was explored for selective oxidation of vanillyl alcohol with molecular oxygen to produce vanillin under atmosphere pressure. In particular, to enhance its efficiency, this catalyst was prepared by adopting different preparation methods namely, template assisted, coprecipitation with and without surfactant, wet‐impregnation, and solution combustion. The prepared catalysts were characterized by XRD, Raman, BET surface area, ICP‐OES, FE‐SEM, HR‐TEM, H2‐TPR, and XPS. Among various catalysts investigated, the template assisted synthesized catalyst exhibited superior activity (100 % conversion and selectivity) and high stability. The better activity of this catalyst was found to be due to reduced crystallite size, high specific surface area (92 m2/g), more surface oxygen, and improved redox behaviour as confirmed from XRD, BET surface area, XPS, and H2‐TPR analysis, respectively. The stability of the catalyst was tested by reusability test and was observed that there is not much decrease in the catalytic activity up to five cycles. Further, the catalytic activity was optimized by varying the reaction parameters such as time, solvent, temperature, and catalyst weight.

Synthesis of a Quaternary Ammonium-Halamine and Preparation on the Modified Nanofibrous Filter with Superior Sterilization, Air Filtration, and Biodegradability.

The outbreak of the 2019 coronavirus pandemic has raised worldwide attention about self-protection from airborne diseases. Air filtration and wearing mask have been proven to be effective measures in reducing the pathogenic aerosol's transmission. Those lead to an increasing demand of high-efficient filters. However, the nonbiodegradable polymeric materials used in filters can accumulate in landfills or ecosystems, potentially causing pollution after improper disposals. Sustainable and biodegradable alternatives to current filter materials are urgently needed. Yet, very few commercial filters meet these needs. In this paper, a novel quaternary ammonium-halamine compound containing Schiff base and a sandwich-structured preparation strategy were developed. The obtained multifunctional filter consists of a PLA fleece as a support layer, an antimicrobial coating for bactericidal function, and a nanofibrous membrane for the particle removal. The filter demonstrates strong bactericidal properties, killing 97% of Escherichia coli and Staphylococcus aureus at a biocide concentration of only 1 mg/mL. It can rapidly kill bacteria within 5 min contact without leaching antimicrobial substances. Furthermore, it boasts a filtration performance with a success rate over 99.99% and a pressure drop of 45 Pa, which surpasses that of commercial N95 filters for PM0.3. Even under humid conditions, it maintains excellent filtration performance. Our reusability testing result of the developed filters shows that a simple halogenation treatment can renew the halamines and restore the filter's antimicrobial activity. The filters can degrade in natural soil. The successful development of this sustainable and biodegradable filter material offers a new alternative for high-performance air quality control that protect public health.

Sugarcane bagasse-derived biochar modified by alkali for enriching surface functional groups to effectively treat ammonium-contaminated water.

In this study, sugarcane bagasse (SB), which was preliminarily treated with H3PO4, was utilized to produce biochar (SB-BC). The SB-BC was subsequently modified with KOH to enrich oxygen-containing functional groups (OCFGs) for the enhanced adsorption of NH4+ from wastewater. Batch tests revealed that KOH-modified SB-BC (SB-MBC) increased the maximum Langmuir adsorption capacity of NH4+ by approximately twofold, from 27.1mg/g for SB-BC to 53.1mg/g for SB-MBC. The optimal operational conditions for NH4+ adsorption onto SB-MBC were pH of 7.0 and a biochar dose of 3.0g/L for the removal of 50mg/L NH4+ at room temperature (25 ± 2°C) over 180min of contact. The enhanced adsorption capacity of NH4+ onto SB-MBC was due to the important contribution of the OCFGs enriched on the surface of biochar, which was increased by about fourfold, after being modified by KOH. The NH4+ adsorption dynamics were better fitted by the Elovich and the NH4+ adsorption isotherms were better described by Langmuir and Sips models, showing that the adsorption process was dominated by monolayer chemisorption. The properties of the adsorption materials before and after adsorption of NH4+ confirmed that cation exchange, electrostatic attraction and surface complexation were the main mechanisms controlling the adsorption process. The desorption and reusability tests of NH4+-saturated SB-MBC revealed that NH4+ adsorption slightly decreased after three successive sorption‒desorption cycles. The findings suggested that SB-MBC is a promising and feasible adsorbent for the effective treatment of NH4+-contaminated water sources. Future work should conduct tests for treatment of NH4+-rich real wastewater and utilize NH4+-saturated SB-MBC as slow releasing fertilizer for plants growth.

Production of 1,3-propanediol via in situ glycerol hydrogenolysis in aqueous phase reforming using bimetallic W-Ni/CeO2.

The production of 1,3-propanediol via in situ glycerol hydrogenolysis and aqueous phase reforming is a promising technique to ensure high product yield with shorter reaction times and lower costs, as demonstrated in this study by investigating the effect of tungsten (W) doping on Ni/CeO2 catalysts. Physicochemical properties of catalyst were determined using XRD, H2-TPR, NH3-TPD, BET, and FESEM-EDX techniques, and the catalytic performance was investigated at 230 °C, 20 bar, and 5 wt.% glycerol in an autoclave batch reactor. W doping ranging from 1-7% improved the catalyst's performance, with 3% W in 10% Ni/CeO₂ (3W10NC) achieving the highest yield (2.4%), selectivity (33.3%), and a good conversion rate (72.18%). The effect of reaction parameter on the 3W10NC catalyst showed that increasing pressure and temperature from the initial parameters had a detrimental effect on 1,3-propanediol attributed to the phenomenon called over-hydrogenolysis. Increasing the glycerol concentration to 20 wt.% also had a positive effect, resulting in the highest 1,3-propanediol yield of 22.27%. The effect of reaction time study revealed that the yield of 1,3-propanediol continued to increase steadily, reaching 38.29% after 4 h of reaction under the optimal conditions of 230 °C, 20 bar, and 20 wt.% glycerol. The kinetic study confirmed that the reaction follows first-order reaction with activation energy of 20.104 kJ mol-1. The catalyst reusability test revealed a decrease in the yield of 1,3-propanediol to 32.55%, likely due to deactivation caused by sintering and leaching, as indicated by the FESEM micrograph, EDX spectra, and NH3-TPD.

Tailored MXene-derived nano-heterostructure oxides for peroxymonosulfate activation in the treatment of municipal wastewaters.

Nowadays, in the field of environmental protection, a huge effort is focused on efficient and sustainable processes to treat wastewaters. The current study emphasizes the photocatalytic performance of TiNbOx, a nano-heterostructure material derived from the oxidation of (Ti0.75Nb0.25)2CTx MXene. The TiNbOx nano-heterostructure exhibited remarkable performance in the degradation of caffeine (CAF) and sulfamethoxazole (SMX) under UVA irradiation in the presence of peroxymonosulfate (PMS). Under optimal conditions, 0.2 g L-1 of TiNbOx, 0.5 mM PMS and 50 μM concentration of pollutants and natural pH of deionized water, we observed a complete degradation of SMX and 91% degradation of CAF. Scavenging studies provided evidence for the involvement of ˙OH and SO4˙- in the degradation of the pollutants, which was also supported by indirect techniques of electron paramagnetic resonance (EPR) spectroscopy. The degradation pathway of the pollutants was analyzed by liquid chromatography-mass spectrometry (LC-MS) and several mechanisms were suggested including hydroxylation and isoxazole ring-opening reactions. In addition, X-ray photoelectron spectroscopy (XPS) supported the proposed degradation mechanism. The reusability test underscored the high stability and efficiency of TiNbOx. Moreover, the significance of this research was emphasized by conducting degradation studies in tap water (TW) and tertiary effluents of the wastewater (WW) treatment plant in Bratislava. Under optimal conditions, 49% and 30% CAF were degraded in TW and WW, respectively, after 12 hours of reaction. For SMX, 68% and 67% degradations were obtained in TW and WW, respectively.

Solar driven highly efficient photocatalyst based on Dy2O3 nanorods deposited on reduced graphene oxide nanocomposite for methylene blue dye degradation.

In recent years, the demand for rare earth elements has surged due to their unique characteristics and diverse applications. This investigation focuses on utilizing the rare earth element dysprosium oxide (Dy2O3) for the photocatalytic oxidation of model pollutants under solar light irradiation. A novel RGO-Dy2O3 nanocomposite photocatalyst was developed using a solvothermal approach, Dy2O3 nanorods uniformly deposited onto reduced graphene oxide (RGO) nanosheets. Comprehensive characterization techniques, including Brunner-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, high resolution - transmittance electron microscopy (HR-TEM), field emission-electron scanning microscopy (FE-SEM), atomic force microscopy (AFM), electron paramagnetic resonance spectroscopy (EPR), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy EIS techniques. The UV-visible diffusive reflectance spectroscopy (UV-Vis-DRS) studies revealed a band gap energy of 3.18eV and a specific surface area of 114 m2/g for the fabricated RGO-Dy2O3 nanocomposite. The RGO-Dy2O3 nanocomposite demonstrated a high photocatalytic degradation efficiency of 98.1% at neutral pH for methylene blue (MB) dye for the dye concentration of 10ppm. The remarkable photocatalytic performance was achieved within 60min under solar light irradiation. Reusability tests demonstrated stability, maintaining over 90% photocatalytic efficiency after three cycles. The EPR spectra and quenching experiments confirmed that photogenerated hydroxyl radicals significantly influence the photodegradation processes. The RGO-Dy2O3 nanocomposite photocatalyst, with its green, easy preparation process and recycling capabilities, presents an ideal choice for various applications. It offers a viable alternative for the photocatalytic degradation of organic dyes in real wastewater, contributing to sustainable environmental remediation.

Development of a MOF-5/g-C3N4 nanocomposite: an effective type 2 heterojunction photocatalyst for rhodamine B dye degradation.

The field of environmental and water remediation faces a significant challenge in removing organic dyes from wastewater, particularly Rhodamine B (RhB), a stubborn dye used in various industries. Traditional treatment methods struggle with its resistance to decomposition, posing risks to water quality, human health, and aquatic life. This study demonstrates a novel approach to enhance photocatalytic efficiency for RhB degradation by constructing a MOF-5/g-C3N4 composite through a facile mechanical grinding method, which is unprecedented. The composite addresses the limitations of g-C3N4, such as rapid recombination of electron-hole pairs, low electron transfer rates, and small surface area, by forming a heterojunction with MOF-5. The composite exhibits enhanced photocatalytic efficiency for the degradation of RhB under sunlight, with a degradation of 91.5% achieved within 90min. Optimization studies highlight the importance of pH and catalyst dosage in the degradation process. The reusability test shows consistent performance over five successive cycles, maintaining a degradation efficiency of over 90%. Total organic carbon (TOC) analyses confirm the mineralization of the dye solution to 82.05% after 90min of irradiation, demonstrating the environmental benignity of the composite. Trapping experiments suggest the involvement of superoxide radicals, electrons, and holes in the photocatalytic mechanism. This study introduces a promising strategy for addressing challenges in dye degradation through innovative composite materials.

Facile fabrication of Cu/kaolin nanocomposite as highly efficient heterogeneous catalyst for 4-nitrophenol reduction in aqueous solution

Hazardous organic pollutants in industrial wastewaters are becoming a major global challenge that threatens life on earth and particularly poses a serious health risk to human beings. 4-Nitrophenol (4-NP) is a highly hazardous organic contaminant that has been extensively utilized across multiple industries, and their wastewater disposal into water streams leads to a higher accumulation of 4-NP. It is therefore important for both academia and industry to make catalysts that are cheap, very effective, good for the environment, easy to recover, and can be used more than once for reducing 4-NP in normal conditions. This paper reports the synthesis, characterization, and application of Cu/kaolin nanocomposite (NC) as an efficient heterogeneous catalyst for decomposing 4-NP, a model organic molecule. The catalyst was synthesized by incorporating a copper precursor into layered kaolin clay and directly reducing the metal precursor using sodium borohydride (NaBH4). The morphology, structure, surface property, and interaction of the resulting Cu/kaolin NC were characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron spectroscopy/energy-dispersive X-ray spectroscopy, selected area electron diffraction, X-ray diffraction, and N2 adsorption/desorption, and the results clearly demonstrated the growth of copper nanoparticles on the kaolin surface. It was discovered that the Cu nanoparticles (NPs) on the kaolin surface had a crystallite size of about 23.6 nm. The significance of Cu NPs and the high catalytic activity of the synthesized Cu/kaolin NC toward 4-NP reduction by NaBH4 were evaluated by the catalytic reduction experiments. Among the different nanocomposites synthesized, 30-Cu/kaolin showed the highest catalytic activity for 4-NP reduction, with a reduction efficiency of over 99 % within 4 min with a pseudo-first-order rate constant, kapp, of 1.23 min−1. Furthermore, the reusability test indicated that Cu/kaolin NC can be reused for up to six runs efficiently without significant decrease in its catalytic performance, indicating the nanocomposite has excellent stability and great potential applications in industrial and agricultural wastewater treatment.

Wet-chemical preparation and physicochemical characterization of nanostructured Zn-Bi2O3/CeO2 composite: A visible-light-driven catalyst for the annihilation of pharmaceutical pollutant

A modified co-precipitation technique assisted with cetyltrimethylammonium bromide (CTAB) surfactant was used to synthesize a nanostructured and zinc-doped mixed metal oxide (Zn-Bi2O3/CeO2) composite. Using X-ray diffraction (XRD), the synthesized nanocomposite was studied in terms of its crystal structure, grain size, percentage crystallinity, and percentage porosity. Energy dispersive X-ray elemental analysis (EDX) was used to ascertain the chemical composition, SEM to confirm the creation of nanostructure material, and Fourier transform infrared spectroscopy (FTIR) to extract the existing functional groups. Investigation of light harvesting properties (UV/Vis) and thermogravimetric analysis (TGA) reveals that the doped composite exhibits a band gap driven by visible light and remarkable thermal stability at high temperatures. The pH value at which a material's net charge is zero, known as pHpzc, is 7.93 for the doped mixed metal oxide composite. The Zn-Bi2O3/CeO2 nanocomposite effectively eliminates 98.4 percent of the quinolone antibiotic (levofloxacin) via a mechanism that integrates sorption and photocatalytic degradation induced by visible light. To determine the optimal circumstances for the efficient operation of a photocatalyst, we experimented with different time intervals, beginning drug concentrations, catalyst dosages, operating temperatures, and pH levels. Reusability tests and post-activity FTIR analysis were used to investigate the long-term usability and structural stability of the newly developed doped composite photocatalyst. The scavenging tests revealed a potential photocatalytic mechanism to explain the annihilation of the levofloxacin drug on the synthesized catalyst. The physicochemical and photocatalytic evaluations recommend that the assembled integrated material has excellent potential for mineralizing medicinal products in pharmaceutical wastes.

Facile hydrothermal synthesis of Bi2Fe4O9/rGO composite for catalytic reduction of 4- nitrophenol

Reduced graphene oxide (rGO) based composites have shown encouraging results in the application field of environmental protection, biology, energy harvesting and energy storage. This article presents a detailed study on the structural, microstructural, optical, and magnetic properties of hydrothermally prepared bismuth ferrite (Bi2Fe4O9)/rGO composite. The catalytic reduction of the toxic 4-nitrophenol into useful 4-aminophenol using the synthesized composite was illustrated. The Bi2Fe4O9/rGO composite sample demonstrated superior catalytic activity compared to pure Bi2Fe4O9, with a reaction rate constant of 0.26398 min–1. The stability and reusability tests forecasted the use of the composites as a low-cost catalyst for wastewater treatment applications.

Synergistic photocatalytic activity of Bi2O3/g-C3N4/ZnO ternary heterojunction with dual Z-scheme charge transfer towards textile dye degradation

It is clear that a wide range of organic substances, including synthetic textile dyes, have the potential to negatively impact the environment. It is crucial to rationally develop highly effective photocatalysts for the degradation of such type of pollutants. In this regard, a heterostructured photocatalyst comes with enhanced charge separation and extended light absorption ability that improves photocatalytic performance. Therefore, In this study, a Bi2O3/g-C3N4/ZnO (BCNZ) ternary heterojunction photocatalyst was synthesized for the degradation of methylene blue (MB) textile dye.. Thermal polycondensation method was opted to synthesize g-C3N4, while ZnO and Bi2O3 photocatalysts were fabricated using co-precipitation method. Similarly, ternary heterojunction of BCNZ was constructed through co-precipitation method. The ternary heterojunction photocatalyst demonstrated better photodegradation ability due to dual Z-scheme charge transfer route. The dual Z-scheme heterojunction enabled the ternary heterojunction to exhibit enhanced light absorption capabilities with reduced recombination rates as well as enhanced charge separation and migration efficiency (confirmed via transient photocurrent response) that resulted in improved photocatalytic performance. The BCNZ dual Z-scheme photocatalyst displayed 92 % of degradation efficiency which was much higher than that of other (binary and pristine) photocatalysts. Scavenging tests and electron spin resonance spectroscopy revealed the significant role of the •O2−, and •OH radicals in the photodegradation of MB. Furthermore, the reusability test presented good stability and recyclability of the ternary photocatalyst with 80 % degradation efficiency after five catalytic cycles.

Hydrophilic Magnetic COFs: The Answer to Photocatalytic Degradation and Removal of Imidacloprid Insecticide

The widespread use of imidacloprid (IMI) in pest control presents significant environmental challenges due to its persistence and low removal efficiency. This study introduces magnetic Covalent Organic Frameworks (COFs) functionalized with Fe₃O₄ nanoparticles (Fe₃O₄@HMN-COF, Fe₃O₄@MAN-COF, and Fe₃O₄@SIN-COF) as efficient adsorbents for IMI removal from water. These COFs, engineered with nitrogen-rich structures and extensive π-electron systems, achieve superior adsorption through π-π interactions, hydrophobic interactions, and hydrogen bonding. Characterization via FT-IR, XRD, and nitrogen sorption isotherms confirmed their high hydrophilicity, stability, and large surface areas. The magnetic properties of the COFs facilitated easy separation from water, enhancing practicality. Kinetic studies for all COFs indicated a pseudo-second-order model, suggesting chemisorption, with adsorption capacities of 600 mg/g for Fe₃O₄@HMN-COF, 480 mg/g for Fe₃O₄@MAN-COF, and 375 mg/g for Fe₃O₄@SIN-COF. Thermodynamic analyses revealed spontaneous and endothermic adsorption processes. Reusability tests showed minimal capacity loss over multiple cycles, underscoring their practical applicability. Practical tests in honey and fruit samples confirmed high efficacy, demonstrating the COFs' versatility. The study also optimized the photocatalytic degradation of imidacloprid using these COFs, with Fe₃O₄@HMN-COF achieving 98.5% efficiency under optimal conditions (10 mg/L IMI, 0.01 g catalyst dose, pH 11, 30°C, UV light). These findings highlight the potential of magnetic COFs for sustainable environmental remediation of pesticide-contaminated water.

Innovative RGO-bridged S-scheme CuFe2O4@Ag2S heterojunction for efficient Sun-light-driven photocatalytic disintegration of Ciprofloxacin

Antibiotics contamination in water bodies poses a significant threat to public health and the environment, necessitating advanced methods for their removal from wastewater. In response to this issue, developing a novel magnetic nanocomposite (RGO/CuFe2O4@Ag2S) as an efficient photocatalyst for the degradation of pharmaceuticals like ciprofloxacin (CIP) is of great importance. The synthesized nanocomposite underwent comprehensive characterization to elucidate its crystalline structure, chemical bonding, surface morphology, elemental composition, internal structure, optical properties, surface area, particle size distribution, and magnetic properties. Under optimized conditions (pH=9, nanocomposite dose =0.5 g/L, CIP concentration of 20 mg/L, and duration of 200 minutes), the nanocomposite demonstrated complete degradation of CIP. Moreover, post-treatment analysis revealed significant reductions in total organic carbon (TOC) and chemical oxygen demand (COD) of 70.08% and 85.08%, respectively, indicating extensive mineralization of the antibiotic. Mechanistic investigations revealed a unique S-scheme heterojunction in the RGO/CuFe2O4@Ag2S nanocomposite, where RGO acts as an electronic bridge between CuFe2O4 and Ag2S. This innovative architecture facilitates efficient charge separation and transfer, significantly enhancing the photocatalytic activity. Reusability tests demonstrated the robust nature of the photocatalyst, with only a modest 6% decline in efficiency after six consecutive cycles. To further assess the system's effectiveness in real-world applications, its performance was evaluated in treating pharmaceutical wastewater. The biodegradation efficiency was quantified by measuring the Average Oxidation State (AOS) and Carbon Oxidation State (COS) of the wastewater samples before and after treatment.

Biodiesel synthesis from low cost biomass wastes and its cost assessment inducing process optimization

This study employed low-cost biomass wastes for the synthesis of biodiesel that is cost-effective and environmentally friendly. The major raw material (oil) was obtained by steam distillation (SD) from Croton heliotropiifolius Kunth leaf (CHKL) and was characterized for its aptness for biodiesel production. Dwarft green coconut husk ash (DGCHA) was used as a bio-adsorbent for acid value reduction of Croton heliotropiifolius Kunth leaves oil (CHKLO). A novel, highly potassium-based catalyst was derived from Karpuravalli banana peels (KBP), calcined, and characterized using TGA, ZETA, FTIR, SEM-EDX, XRF-FS, and BET analysis. Biodiesel was synthesized using a microwave-assisted method, characterized, and compared with the recommended standard. The catalytic strength of the calcined Karpuravalli banana peel powder (CKBPP) was tested using a reusability test, and the cost evaluation of production was estimated. Results showed that the CHKL was rich in oil (43% wt./wt.), and the oil is highly acidic (5.23 mg KOH/g oil). At high particle size, the dwarf green coconut husk ash (DGCHA) bagasse reduced the acid value to a minimum (1.4 mg KOH/g oil) at 3 days. The developed novel catalyst from CKBPP indicated high potassium-calcium contents for base transesterification. Process optimization indicated that the predicted response data of 95.285% (wt./wt.) at T1 = 90 min, T2 = 60 oC, T3 = 4.5% (wt.), and T4 = 9 (vol./vol.) was validated in triplicate, and the average data value of 95.10% (wt./wt.) was established. Dataset on the quality of biodiesel showed that the produced biodiesel properties were in line with recommended standards. Economic appraisal data showed that the cost of producing 20 L of CHKLOB (biodiesel) was $4.73 at 1,500 to $1. The study concluded that the production of biodiesel from waste can be cost-effective and environmentally friendly if wastes are harness.Graphical

Biosynthesis of TiO2/CuO and Its Application for the Photocatalytic Removal of the Methylene Blue Dye.

In this study, we successfully synthesized a TiO2/CuO nanocomposite using the aqueous extract of Impatiens tinctoria A.rich. leaf extract as a capping, reducing, and stabilizing agent for the first time in an environmentally friendly, low-cost, straightforward, and sustainable technique. Numerous characterization techniques such as ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS), photoluminescence (PL), Raman spectroscopy, Fourier-transform infrared (FTIR), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and high resolution TEM (HRTEM) were used to characterize the obtained TiO2/CuO nanocomposite. XRD verified that the TiO2/CuO nanocomposite has an average crystallite size of about 21 nm. The TEM result revealed an average particle size of 29 nm for the biosynthesized TiO2/CuO NC. The HRTEM analysis showed the presence of polycrystalline structures with the predominant lattice fringes 0.352 and 0.19 which were attributed to anatase phase TiO2 in the crystal plane of (101) and (200), respectively. The lattice fringes for monoclinic CuO were observed with values of 0.213 and 0.252 for the lattice planes of (111) and (111̅), respectively. The photoluminescence spectroscopic analysis revealed that the TiO2/CuO NC showed the lowest intensity compared to the pristine TiO2 and CuO indicating the reduction of exciton recombination in the case of the TiO2/CuO NC. The BET analysis showcased the formation of mesoporous materials with a surface area of 87.5 m2/g. The photocatalytic degradation performance of the biosynthesized TiO2, CuO, and TiO2/CuO nanomaterials against the potentially harmful MB dye was tested using the light source of a 150 tungsten-halogen lamp with a wavelength range of 360-2800 nm. The factors affecting photodegradation efficiencies like catalyst dose (20 mg), dye concentration(15 ppm), pH (9), and reaction time (90 min) were optimized for the degradation of the MB dye. The TiO2/CuO catalyst showed the highest degradation efficiency of 99% under the optimized conditions. The degradation rate of the MB dye in the presence of the TiO2/CuO NC was evaluated and found to be fitted to the pseudo-first-order kinetics with a rate constant of 0.03 min-1. The reusability test of the TiO2/CuO catalyst showed its good stability.

Assessing the Stability and Photocatalytic Efficiency of a Biodegradable PLA‐TiO2 Membrane for Air Purification

AbstractThe potential of a biodegradable polylactic acid (PLA)‐TiO2 membrane for air purification is investigated, utilizing the environmentally friendly solvent Cyrene. Through the integration of TiO2 nanoparticles within a PLA matrix, the membrane is used to degrade ethanol as a model volatile organic compound (VOC) under UV light. Scanning Electron Microscopy (SEM), Energy Dispersive X‐ray Analysis (EDX), and UV–vis spectrophotometry confirm the porous structure of the membrane, the even distribution of TiO2, and its effective band gap of 3.06 eV, respectively. Ethanol adsorption is best described by the Langmuir isotherm model, suggesting monolayer coverage on a homogeneous surface. Photocatalytic tests demonstrate that the membrane decomposes ethanol (6800 ppm) within 14 min under UV light, generating acetaldehyde, acetic acid, formaldehyde, and formic acid as intermediates, and ultimately producing CO2 and water. Reusability tests indicate a decrease in decomposition time over successive cycles due to increased TiO2 exposure from the gradual degradation of PLA. However, this degradation poses challenges for continuous use, compromising the membrane's long‐term durability.

Improving sample preparation by biochar-coated sampling tubes: proof-of-concept extraction of sex hormones from real waters

This work showcases a novel application of biochar for analytical sample treatment. The carbonaceous material, obtained by pyrolysis of orange peel waste (550°C) without any post-synthesis treatment or functionalization, was thoroughly characterized and easily immobilized on the inner wall of sampling tubes in order to perform a sort of “in-vial” solid-phase extraction (SPE). The as-obtained device was tested for the extraction of seven sexual steroids, as probe water pollutants, from tap, lake, river water and wastewater treatment plant effluent samples spiked with 0.2-5 µg L−1 of each compound. The sorption kinetics profiles showed quantitative uptake from the sample (25 mL) in 20 min contact time, followed by complete elution in pure ethanol (2 mL, 15 min), thanks to the proper balance between sorption affinity and ease of elution. Under the selected conditions, recovery was in the range 60-123 %, with good inter-day precision (RSD 10-18 %, n=3). As evidence of the excellent reproducibility, an overall RSD below 15 % was observed from inter-day inter-batch recovery tests on three individually prepared sampling tubes. The procedure, carried out on a roller mixer, allows 10 samples to be extracted simultaneously, improving the sample throughput. Moreover, reusability tests showed that the same device maintains its efficiency for 10 consecutive sorption/desorption cycles. The greenness assessment, carried out by two dedicated software, further supported the sustainability of this biochar-based sample preparation as an alternative SPE.

Novel algae-chitosan/alginate beads for efficient basic Fuchsin removal: Synthesis, characterization, adsorption study, mechanism, and optimization

In this study, utilized algae activated with citric acid and lime juice to develop a novel bioadsorbent, The Algae@CS/Alginate beads were formed by encapsulating the activated algae with chitosan and alginate, producing a nanocomposite that is efficient in removing Basic Fuchsin (BF) dye from water. The beads were characterized by means of a diversity of techniques, such as FTIR, XRD, XPS, SEM and determination the surface area via N2 adsorption/desorption isotherm that permitted that the adsorbent has high surface area 124.43 m2/g. The electrical properties of the BF, including its structure and reactivity, were determined by density functional theory (DFT). The MEP data and the molecular orbitals (HOMO and LUMO), as well as the sites of the electrophilic besides nucleophilic attack places, correspond fairly well, according to DFT. The adsorption process was fitted to Langmuir isothermally, and kinetically to pseudo-second-order (PSOE) model. The adsorption mechanism was identified as chemisorption with an adsorption energy of 32.6 kJ/mol. Thermodynamic research shows that the BF adsorption process by Algae@CS/Alginate beads is spontaneous and endothermic because of the positive ΔHo and negative ΔGo. Through numerical optimization of the programmed, the ideal conditions for adsorption were strongminded to be a pH of 8, a dosage of 0.02 g/25 mL for Algae@CS/Alginate beads, and a concentration of 367.27 mg/g of BF. Using the least amount of intended experiments, the adsorption procedure was optimized by the request of Box-Behnken design (BBD) and answer surface methodology (RSM) in Design-Expert software. Adsorbent reusability test results showed that, following eight successive cycles of adsorption and desorption, the adsorbent was stable and that removal efficacy had not decreased. It additionally demonstrated good efficacy, no alteration in chemical conformation, and the same XRD and FTIR data before and after recycle. Analyze the interaction between the Algae@CS/Alginate beads and the BF.

Preparation and characterization of hierarchically porous hybrid gels for efficient dye adsorption.

Water treatment faces significant challenges due to the increasing complexity of pollutants and the need for more efficient, sustainable treatment methods. However, current adsorbent materials often struggle with issues such as low adsorption capacity, slow kinetics, and poor reusability, limiting their practical application. In this study, we developed a novel hierarchical porous hybrid gel (HPHG) for water treatment to address the limitations of conventional adsorbents. The HPHG features a multi-level porous structure (from 48 ± 28 nm to 4385 ± 823 nm) that significantly enhances its porosity and specific surface area. We systematically investigated the relationship between the material's structure and its adsorption performance. Kinetic studies revealed a tendency towards a pseudo-second-order adsorption model, attributed to the material's unique structural features that facilitate rapid mass exchange channels inside HPHG and provide abundant active sites for pollutant adsorption. Reusability tests demonstrated that the material retained 85.4% of its initial adsorption capacity after five adsorption-desorption cycles, highlighting its potential for practical applications. This study provides valuable insights into structure-performance relationships in advanced water treatment materials, offering a promising approach for designing next-generation adsorbents with superior efficiency and sustainability.

Development of a novel lightweight brick-activated carbon based BiVO4 photocatalyst and its adsorption-photocatalytic behavior for toxic dye removal in wastewater

The purpose of this research was to develop a novel photocatalyst by loading BiVO4 (BVO) particles on lightweight brick-activated carbon (LWB-AC). The characterizations of as-prepare samples were studied using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–VIS –NIR spectrophotometer (UV-VIS-NIR) techniques. The adsorption-photocatalytic methylene blue (MB) removal, methyl orange (MO) removal and rhodamine B (RhB) removal of the as-prepared LWB-AC based BVO photocatalyst were tested by irradiating visible light. The results showed that the LWB-AC based BVO photocatalyst exhibited the highest adsorption-photocatalytic efficiency for the removal of MB, MO and RhB dyes under visible light irradiation as compared to the other samples. This might be due to the synergistic effect between AC and BVO on the surface of LWB. Moreover, the presence of both AC and BVO on the surface of LWB helped in preventing the electron-hole recombination, resulting in the enhanced adsorption-photocatalytic activity. For reusability tests, the LWB-AC based BVO photocatalyst did not show the loss of adsorption-photodegradation ability of MB, MO and RhB dyes after five runs. A probable adsorption-photodegradation mechanism of LWB-AC based BVO photocatalyst was also proposed.