Reusability Test Research Articles

Effect of the amount and type of active metal and its impregnation sequence on bio-fuel production

This study aims to investigate biofuel production from biomass-derived bio-oil and examine the impact of selecting different active metals, their quantities, and synthesis procedures on biofuel selectivity. For this purpose, alumina-supported catalysts containing Zr, Co, and W were prepared using the wet impregnation method. Some physical and chemical properties of the synthesized catalysts were determined through XRD, BET, SEM/EDS, ICP-MS, TGA-DTA, and DRIFTS analysis. The activity test studies revealed that the 5Co-10Zr@MA catalyst, prepared by co-impregnation, exhibited the highest bio-oil conversion (95 %) and the highest iso-paraffin selectivity (93 %). XRD analysis indicated that this catalyst possess the CoAl2O4 structure, indicating the formation of an alloy between alumina and cobalt, thereby enhancing catalytic activity. The reusability tests showed that the 5Co-10Zr@MA catalyst maintained its activity over a time of 3 h. Consequently, the utilization of mesoporous alumina-supported bimetallic catalysts has proven to be successful in the production of biofuels, achieving high conversion and selectivity.

Nonthermal plasma processing catalyzed by CuFe2O4 for organic pollutants remediation and bacterial inactivation with density functional theory

The suggested nonthermal plasma has been employed for organic pollutants remediation and bacterial inactivation with catalyst (CuFe2O4) via reactive oxygen and nitrogen species, along with catalytic density functional theory processing. The plasma generated species O2− (g.), OH• (g.), H2O2 (aq.), and NOx (aq.) are used for the remediation of organic pollutants, such as reactive black5 and bromocresol green with catalytic oxidative and reductive transformation, like as from Fe2+ (aq.) to Fe3+ (aq.) and from Cu2+ (aq.) to Cu1+ (aq.), respectively. In the presence of plasma with CuFe2O4, the pollutants remediation enhanced more, which is 95 ± 0.78%, rather than only plasma. After removal of pollutants, the plasma processing catalyzed by CuFe2O4 was highly inactivated the E. coli. bacterial growth, which inhibition rate is 100 ± 0.87% and 100 ± 0.69% for reactive black5 and bromocresol green, rather than only plasma, such as 86.41 ± 0.91% and 73.91 ± 0.56%, respectively. The CuFe2O4 generated super oxides (O2− (aq.)) and hydroxides (H+(aq.), OH⦁(aq.), and OOH⦁(aq.)) are rapidly react with bacteria to damage the bacterial cell membrane via catalytic redox process. However, the plasma generated species were react with catalyst to produce the e− charge densities under the redox transformation of spin orientation (±) 0.58 e−, which is 0.007, 0.009, and 0.005 electrons per cubic Angstrom, for CuFe2O4, H2O2(aq.), and NOx(aq.). The plasma generated species concentrations were quantified in the deionized water, which are H2O2(aq.) (145 ± 0.91 μM) and NOx(aq.) (112 ± 0.56 μM), respectively. After eradication of pollutants, the water pH was observed, which is near to the neutral at 6.57 ± 0.27 under the catalytic binary redox process. Moreover, the catalytic stability examined via reusability test, which were four cycles for reactive black5 and three cycles for bromocresol green. Furthermore, the CuFe2O4 nanoparticles conducted several characterizations to analyze the various properties, such as crystal, surface, functional, and elemental.

2D/2D Schottky-type hybrid heterocatalyst comprising S-doped g-C3N4 and delaminated Ti3C2 MXene: Synergistic interplay of dual strategies for effective H2 generation and pollutant degradation

The quest for sustainable solutions to environmental pollution and energy scarcity has prompted the exploration of advanced photocatalytic materials. This study introduces an efficient 2D/2D Schottky-type hybrid heterocatalyst that combines sulfur-doped 2D g-C3N4 (SCN) with delaminated 2D Ti3C2 (TC) MXene, designed for effective H2 generation and antibiotic pollutant degradation under visible light. This hybrid system leverages the synergistic interplay of two strategies: electronic band structure engineering and conductive TC MXene cocatalyst integration, addressing the critical limitations inherent in g-C3N4. The TC-4/SCN hybrid, with its optimized TC content, exhibits exceptional photocatalytic performance, achieving an H2 production yield of 79.5 μmol over 5 h and an apparent quantum efficiency of 9.2 %. Moreover, this hybrid demonstrates significant effectiveness in degrading and mineralizing the antibiotic levofloxacin, surpassing g-C3N4, SCN, other TC/SCN hybrids, and several advanced photocatalysts previously reported. Detailed characterization and mechanistic investigations attribute the outstanding photocatalytic activity to efficient charge transfer, separation, reduced recombination rates, strong optical absorption, and a large specific surface area, all of which are facilitated by the dual strategies employed in creating the 2D/2D Schottky-type heterojunction. Furthermore, reusability tests confirmed the durability and stability of the TC-4/SCN, highlighting its practical applicability for repeated use in environmental and energy applications.

Biochar from Date Palm Waste via Two-Step Pyrolysis: A Modified Approach for Cu (II) Removal from Aqueous Solutions

Heavy metals such as copper, often discharged from industrial processes and agricultural activities, pose significant environmental and health risks due to their toxicity, particularly in the soluble form of Cu (II). This study investigates the effectiveness of biochar produced from date palm leaf midrib waste via a two-step pyrolysis process, as a sustainable and economical adsorbent for removing Cu (II) from aqueous solutions The biochar was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) surface area analysis. Adsorption experiments were conducted to evaluate the effects of pH, adsorbent dosage, contact time, and initial Cu (II) concentration. The maximum adsorption capacity was observed at pH 6, with a capacity of 70 mg/g. The adsorption data were best described by the pseudo-second-order kinetic model, indicating chemisorption as the primary mechanism. Thermodynamic studies indicated that the adsorption process was spontaneous and exothermic, with a Gibbs free energy change (ΔG) of −1.245 kJ/mol at 25 °C, enthalpy change (ΔH) of −15.71 kJ/mol, and entropy change (ΔS) of 48.36 J/mol·K. Reusability tests demonstrated that the biochar retained over 85% of its initial adsorption capacity after five cycles, with capacities of 60 mg/g in the first cycle, decreasing to 52 mg/g by the fifth cycle. This study highlights the potential of biochar derived from date palm waste as an efficient, sustainable adsorbent for the removal of Cu (II) from wastewater, contributing to both environmental management and waste valorization. Future research should focus on optimizing the biochar production process and exploring its application for the removal of other contaminants.

Construction of novel BiOI/CuInS2/ZnO dual S-scheme charge transfer pathway for efficient antibiotic degradation

The present work explored the photocatalytic activity of BiOI–CuInS2–ZnO ternary heterojunction for the photodegradation of the tetracycline (TCl). The bare photocatalysts were prepared via hydrothermal method while the ternary heterojunction was synthesized using simple physical mixing route. The ternary heterojunction of BiOI, CuInS2 and ZnO followed the S-scheme charge transfer pathway exhibiting superior photodegradation ability compared to other synthesized photocatalysts. The attained degradation efficiency of BiOI–CuInS2–ZnO S-scheme ternary heterojunction was 96.75 % within 90 min of light illumination which was much higher than other photocatalysts. Electron spin resonance (ESR) investigations and scavenging experiment indicated that •O2−, and •OH radicals plays an important role in photodegradation of TCl. Furthermore, the structural analysis of synthesized bare photocatalysts was also done via density functional theory (DFT) calculations. The results showed that after the formation of S-scheme heterojunction, the ternary heterojunction showed lower recombination rate (validated via PL analysis) with boosted charge carriers separation rate (confirmed through EIS and TPR analysis) and light absorption ability. This had led to upgradation in photodegradation efficiency of ternary BiOI–CuInS2–ZnO photocatalyst. The reusability test of the photocatalysts confirmed excellent stability of ternary photocatalysts with 90.25 % degradation rate up to five catalytic cycles.

Assembly of 2D/2D Bi2WO6/Boron-doped g-C3N4 Z-type heterojunction photocatalysts for efficient antibiotic adsorption and degradation

The photocatalytic heterojunction systems have shown remarkable development in improving the efficiency of visible-light absorption and photocarriers separation. Herein, we successfully engineered efficient 2D/2D Bi2WO6/Boron-doped g-C3N4 (BiWO/BCN) architectures as Z-type heterojunction photocatalysts with different BiWO to BCN ratios for degradation of antimicrobial drug sulfamethoxazole (SMX) under visible illumination. The SMX degradation using the optimized 40%BWO/BCN sample was obviously enhanced, and the degradation rate was 99.3 % after 120 min of irradiation. Its degradation efficiency was 6.5-, 3.2-, and 2.9-times better than that of BiWO, CN, BCN, and, respectively. The significantly boosted performance of the BiWO/BCN photocatalyst was credited to the effective separation of photo-excited electron and hole pairs. The SMX photodegradation pathways have been explained with a complete assessment of the active species, which showed the major role of •O2− and electrons. The reusability tests proved the high photostability of 40%BiWO/BCN sample throughout 5 sequential cycles (only 3.8 % reduction was witnessed). Therefore, this work presents an innovative photocatalyst combination for green degradation of SMX antibiotic.

Heterogeneous electro-Fenton removal of polyacrylamide in aqueous solution over CoFe2O4 catalyst.

Polyacrylamide (PAM) in environmental water has become a major problem in water pollution management due to its high molecular mass, high viscosity and non-absorption by soil. CoFe2O4 with strong magnetic properties was prepared by solvent-thermal synthesis method and used as the catalyst for the removal on PAM in heterogeneous Electro-Fenton (EF) system. It showed that the removal efficiency of PAM by the heterogeneous EF system using CoFe2O4 catalyst was 92.01% at pH 3 after 120 min. Further studies indicated that ·OH was the most significant active species for the removal of PAM, and the contribution of ·O2- and SO4·- for the removal of PAM was less than 15%. The reusability test and XRD, XPS, FTIR analyses proved that the catalyst had good stability. After a repeated use for five times, the catalyst still had a high PAM removal rate and stable structure. The valence distribution and functional groups of the phase components of the catalyst did not change significantly before and after the reaction. The possible mechanism of catalyst activation of H2O2 was deduced by mechanism investigation. The CoFe2O4 is an efficient and promising catalyst for the removal of PAM wastewater.

A simple and high-performance cellulose nanocrystal based biocatalytic Pickering emulsion system for pharmaceutical molecule vitamin E nicotinate

The use of Pickering emulsions for biocatalysis is gaining increased attention. However, the extensive application is greatly limited due to the enzyme inactivation. Herein, a biocatalytic Pickering emulsion with high-performance utilizing cellulose nanocrystals immobilized lipases (CNCs-Lps) particles as stabilizer is advanced and applied for the synthesis of Vitamin E nicotinate. CNCs-Lps display high activity and reusability due to the construction of biocatalytic microreactor in the O/W emulsion system. The yield of vitamin E nicotinate ester reached up to 83 %. More importantly, the CNCs-Lps can be reused due to the similar principles to microreactors in Pickering emulsions. Reusability test showed that the CNCs-Lps could be recovered from the emulsion system by centrifugation and the yield of vitamin E nicotinate retains 78 % of initial value after five cycles, demonstrating overwhelming advantage than the fair counterpart with free lipases.

Solar photocatalytic degradation of ciprofloxacin using biochar supported zinc oxide- tungsten oxide photocatalyst.

Ciprofloxacin (CIP) is an antibiotic used to treat bacterial infections. It is not completely broken down during conventional wastewater treatment processes and can persist in the environment, leading to the development of antibiotic-resistant bacteria. This study focuses on the solar photocatalytic degradation CIP using biochar-supported photocatalysts. The photocatalysts developed by combining ZnO and WO3 in different ratios (1:2, 1:1, 2:1) were supported on hemp herd biochar. The photocatalyst made with a ratio of 2:1:1 of ZnO:WO3:biochar (Z2W1H) reported the highest CIP degradation efficiency of 87.3% and TOC removal efficiency of 43.1% at a catalyst dosage of 2g/L, initial CIP concentration of 3mg/L, and treatment time of 150min. Subsequently, the effects of operating parameters on CIP degradation were investigated using central composite design (CCD). About 85.4% degradation efficiency of CIP was obtained at optimum conditions (pH ∼8.4, initial CIP concentration ∼4.4mg/L, catalytic dosage ∼3.4g/L) within 90min. A quadradic model was developed to interpret the linear and interactive effect of operating parameters on the CIP degradation efficiency with 2.24-4.59% error. The adsorption-desorption study showed around 42.21% of adsorbed CIP was desorbed from Z2W1H. Scavenger studies demonstrated that the CIP breakdown was notably done by the superoxide radical (O2•-). The mechanism of CIP degradation was adsorption on biochar and subsequent degradation by photocatalyst. The prevalent degradation reactions such as C-N bond cleavage, decarboxylation, decarbonylation, defluorination, and ring opening lead to formation of various intermediates. The Z2W1H reusability test showed ~ 4.2% decrease in CIP removal efficiency after three cycles.

Conversion of secondary aluminum dross into hierarchical carbonate-intercalated Mg-Al layered double hydroxide for efficient CO2 capture

This paper explores the preparation of hierarchical Mg-Al layered double hydroxide (LDH) from secondary aluminum dross waste for the first time. The aluminum content of the waste was initially extracted in the form of a sodium aluminate solution using a multistep wet chemical process. CO3-intercalated Mg-Al LDH was then prepared at pH values of 9 and 11 by adding magnesium chloride to a mixed solution of sodium aluminate and sodium carbonate. The X-ray diffraction (XRD) analysis revealed that a pure LDH structure could be formed at pH 11. The quantification of the XRD data revealed that the synthesized LDH had an interlayer spacing of 3.1 Å. The microstructural porosity was 0.76 cm3/g, and the specific surface area was 134 m2/g. The field emission scanning electron microscopy (FESEM) analysis revealed a hierarchical layered structure composed of flake-like particles in the microstructure. The elemental mapping of the synthesized LDH showed a proper distribution of Mg, Al, C, and O. The synthesized Mg-Al-CO3 LDH was then used for a study on CO2 capture. The CO2 capture experiments demonstrated that the amount of CO2 adsorption is influenced by temperature, gas pressure, adsorbent mass, and exposure duration. Investigating the effects of time and temperature revealed that a CO2 adsorption of 0.94 mmol/g can be achieved at a temperature of 25 °C during a 90-minute exposure period. Varying the gas pressure from 1 to 2.5 bar, while maintaining a constant temperature of 25 °C and an adsorbent mass of 1.5 g, resulted in an increase in CO2 adsorption from 1.7 to 2.3 mmol/g. Reusability tests showed that the LDH could maintain a satisfactory adsorption value of 0.84 mmol/g after 5 cycles, indicating its potential for repeated use.

Synthesis of biofuel from Luffas cylindrical-Dennettia tripetala oil blend (BT40) using catalytic sweet corn stock acidified with iron (III) sulfate (Fe2(SO4)3)

In an attempt to model and optimize the biodiesel production from the binary oil blends, a BTO40 obtained from the mixture of Dennettia tripetala (DTO) and Luffas cylindrical (LCO) oilseeds was employed in a double-stage microwave-assisted batch process (DSMABP). The DTO40 was esterified with iron (III) sulfate (Fe2(SO4)3) and then transesterified with catalyst selectivity between calcined fermented sweet corn stock (CFCS) and calcined non-fermented sweet corn stock (CNFCS). Catalyst characterization was carried out using analyzers, while process modeling and optimization were carried out using statistical tools. The produced biodiesel qualities were evaluated, and the catalyst potential was tested by a catalyst reusability test. Results show that a BTO40 was suitable for maximum biodiesel yield of 98.92% (wt./wt.) with HHV of 43.84 MJ/kg, CN of 79.73, flash point of 120 °C, cloud point of -3 °C, pour point of -6 °C, cold filter plugging point of +2 °C, oxidative stability of 4.6 h, and carbon residue of 0.02% nm. The statistical modeling and optimization by RSMI-Optimal predicted a mean value of biodiesel to be 99.28% (wt./wt.), the ANNGA predicted a mean biodiesel yield of 99.78% (wt./wt.), and γGCFW predicted 99.82% (wt./wt.), respectively, at different variable conditions. These values were validated in triplicate, and the average means were obtained as 98.57% (wt./wt.), 99.69% (wt./wt.), and 99.71% (wt./wt.), respectively. Catalyst usability tests show DFSCS has high alkali potential as a base catalyst. The produced biodiesel properties are in total agreement with the recommended biodiesel standard. The study concluded that BTO40 treated with a 0.1 M Fe2(SO4)3 solution in a base-catalyzed calcined fermented sweet corn stock for biodiesel synthesis can be used as an alternative fuel.

Optimization of Matrix Components for Improved Catalytic Activities of Cellulase Immobilized on Biochar-Chitosan Beads

Bioethanol is a renewable energy that is gaining popularity globally. It’s biochemical production requires the use of enzyme, especially cellulase. Cellulase is an enzyme that catalyzes the degradation of cellulose and related polysaccharides which finds applications in food, textiles, detergents, biofuels etc. However, the worldwide use of cellulase is limited by its relatively high production costs and low biological activity. This study was design to locally produce biochar-chitosan beads at optimized conditions to immobilize cellulase for improved thermal and storage stability as well as ensure reusability of the enzyme so as to improve biological activity and avoid the continuous production of free cellulase thereby reducing the production cost. Biochar was produced by pyrolyzing sugarcane bagasse in a local airtight chamber for 1 hour. Beads were formed from different ratios of biochar and chitosan in varying concentrations of calcium chloride solution as generated by design expert software version 13. The beads were dried in an oven at 50 0C for 24 hours and functionalized in 25% glutaraldehyde (GDA). The beads were loaded with enzyme (10.06 µmole/min/mL) at room temperature (27 ± 3 oC). Enzyme activity, thermal stability, storage stability and reusability tests were carried out according to standard procedures. The half-life and activation energy were also evaluated. The result showed that the optimum activity of the loaded enzyme (2.63 µmole/min/mL) was obtained when 2.46 g of porous biochar was mixed with 2.48 g chitosan in 5 % Calcium chloride aqueous solution. The immobilized enzyme was able to maintain thermal stability between 30 oC and 70 oC while the activity for free enzyme started declining after 50 oC. Also, the activation energy for immobilized cellulase enzyme (23.17 KJ/mol) was lower than the activation energy (55.146 KJ/mol) for free cellulase. The half-life, when stored at ambient Temperature (27 ± 3 oC), for free enzyme was 0.4 days while the half-life for immobilized enzyme was 3.59 days. Therefore, cellulase immobilized on support locally produced at optimal conditions had improved catalytic properties when compared to the free enzyme. Hence, more indigenous materials and practices may be employed for a cost effective and cheaper industrial processes.

Optimization of hydrochar production from cigarette filters for enhanced CO2 adsorption

In this study, CO2 capture using Hydrochar adsorbents synthesized from Cigarette Filter, specifically H-208 and HA-204, was rigorously investigated. Optimization using RSM was applied to fit a quadratic model to the data with F-value of 184.95 and R2 of 0.9847. H-208 and HA-204 display maximum CO2 adsorption capacities of 1028.35 mg/g and 1003.35 mg/g, respectively, at 9 bar and 25 °C. Isotherm studies ranked Freundlich and Sips models as effective descriptors, highlighting differences in adsorption behavior between HCs synthesized at different conditions. Kinetic modeling identified the Elovich model as suitable for predicting time-dependent CO2 adsorption. Thermodynamic analysis revealed differences in adsorbent affinity and spontaneity between HCs, with higher enthalpy values for H-208 indicating stronger adsorbent-adsorbate interactions. ΔH° values of −61.863 kJ/mol for H-208 and -47.442 kJ/mol for HA-204, signifying an exothermic adsorption process. The CO2 adsorption mechanism involves physical and chemical processes influenced by the polar structure, surface area, and functional groups of HCs. The effect of HCl on CO2 adsorption is insignificant, and the use of HCl only reduces the synthesis time. Adsorbent reusability tests showed minor capacity declines over multiple cycles, indicating their potential in environmental remediation and industrial gas separation processes.

Ag-Incorporated Cr-Doped BaTiO3 Aerogel toward Enhanced Photocatalytic Degradation of Methyl Orange.

A novel Cr-doped BaTiO3 aerogel was successfully synthesized using a co-gelation technique that involves two metallic alkoxides and a supercritical drying method. This freshly prepared aerogel has a high specific surface area of over 100 m2/g and exhibits improved responsiveness to the simulated sunlight spectrum. Methyl orange (MO) was chosen as the simulated pollutant, and the results reveal that the Cr-doped BaTiO3 aerogel, when modified with the noble metal silver (Ag), achieves a pollutant removal rate approximately 3.2 times higher than that of the commercially available P25, reaching up to 92% within 60 min. The excellent photocatalytic performance of the Ag-modified Cr-doped BaTiO3 aerogel can be primarily attributed to its extensive specific surface area and three-dimensional porous architecture. Furthermore, the incorporation of Ag nanoparticles effectively suppresses the recombination of photo-generated electrons and holes. Stability and reusability tests have confirmed the reliability of the Ag-modified Cr-doped BaTiO3 aerogel. Therefore, this material emerges as a highly promising candidate for the treatment of textile wastewater.

Novel self-cleaning PVDF/MoO3/ZnO/GO dual layer hollow fiber photocatalytic membrane with excellent photocatalytic performance of EDCs removal and energy storage capability

Endocrine-disrupting chemicals (EDCs) have a wide range of detrimental effects on health, particularly on the human endocrine system. Efflux This research study involves the application of - molybdenum trioxide, zinc oxide and graphene oxide (MoO3/ZnO/GO) with polyvinylidene fluoride (PVDF) membrane as photocatalytic dual layer hollow fiber (DLHF) membrane as novel energy storage photocatalytic membrane towards efficient degradation of EDCs under visible light illumination. Ternary MoO3/ZnO/GO was synthesized using hydrothermal method and was embedded on the surface of dual layer hollow fiber membrane by dry-wet spinning method by varying the GO loading at 0.1, 0.25 and 0.5 wt%. The results indicated that the 0.5 PVDF/MoO3/ZnO/GO DLHF photocatalytic membrane exhibited improved wettability, high porosity, good water flux, and exceptional EDCs removal, achieving removal rates of 73.08%, 75.80%, 73.65%, 100%, 95.57%, and 53.50% for 1 mg/L BPA, 1 μg/L BPA, 2 μg/L gabapentin, 1 μg/L diclofenac, 10 μg/L caffeine, and 6 μg/L nonylphenol, respectively after 240 min of light exposure. Besides, energy storage capability achieved 96.07% rejection of 1 mg/L BPA in dark condition while stability and reusability test showed 0.5 PVDF/MoO3/ZnO/GO DLHF achieve 74.02% regeneration efficiency after 3 consecutive cycles. Furthermore, the photocatalytic properties of 0.5 PVDF/MoO3/ZnO/GO DLHF could assure a self-cleaning property and increase its lifetime. The PVDF/MoO3/ZnO/GO DLHF photocatalytic membrane served as a versatile 3-in-1 solution, enhancing photocatalytic degradation and rejection capabilities while also serving as a promising energy storage material with self-cleaning properties for removing EDCs from aquatic environments, regardless with or without the presence of light.

A Phosphorylated Dendrimer-Supported Biomass-Derived Magnetic Nanoparticle Adsorbent for Efficient Uranium Removal.

A novel biomass-based magnetic nanoparticle (Fe3O4-P-CMC/PAMAM) was synthesized by crosslinking carboxymethyl chitosan (CMC) and poly(amidoamine) (PAMAM), followed by phosphorylation with the incorporation of magnetic ferric oxide nanoparticles. The characterization results verified the successful functionalization and structural integrity of the adsorbents with a surface area of ca. 43 m2/g. Batch adsorption experiments revealed that the adsorbent exhibited a maximum adsorption capacity of 1513.47 mg·g-1 for U(VI) at pH 5.5 and 298.15 K, with Fe3O4-P-CMC/G1.5-2 showing the highest affinity among the series. The adsorption kinetics adhered to a pseudo-second-order model (R2 = 0.99, qe,exp = 463.81 mg·g-1, k2 = 2.15×10-2 g·mg-1·min-1), indicating a chemically driven process. Thermodynamic analysis suggested that the adsorption was endothermic and spontaneous (ΔH° = 14.71 kJ·mol-1, ΔG° = -50.63 kJ·mol-1, 298. 15 K), with increasing adsorption capacity at higher temperatures. The adsorbent demonstrated significant selectivity for U(VI) in the presence of competing cations, with Fe3O4-P-CMC/G1.5-2 showing a high selectivity coefficient. The performed desorption and reusability tests indicated that the adsorbent could be effectively regenerated using 1M HCl, maintaining its adsorption capacity after five cycles. XPS analysis highlighted the role of phosphonate and amino groups in the complexation with uranyl ions, and validated the existence of bimodal U4f peaks at 380.1 eV and 390.1 eV belonging to U 4f7/2 and U 4f5/2. The results of this study underscore the promise of the developed adsorbent as an effective and selective material for the treatment of uranium-contaminated wastewater.

Facile physical entrapment of halochromic dye via UV-photografting for the fabrication of colorimetric cotton sensors to detect toxic ammonia gas

Textile-based halochromic gas sensors are useful for detecting volatile organic compounds (VOCs) such as ammonia, because they undergo changes that are distinguishable to the naked eye. Herein, we report the UV photografting system we developed for the fabrication of halochromic cotton sensors with reduced amounts of salt, resources, and effluents. First, 4-hydroxycoumarin-based dye (HD) was synthesized as a halochromic indicator, where after the synthesized dye, monomer, and photoinitiators were introduced to a dye bath to fabricate the UV photografting system. This system was produced by grafting monomers on a fiber surface under UV light irradiation to formulate a polymer network that entraps dye molecules. A series of different monomer concentrations and photoinitiators were introduced to the dye bath. Subsequently, the dyeability and gas detection performance of the fabricated cotton sensors were evaluated. In addition, fastness and reusability tests were performed to ensure the fabricated cotton sensors were durable and sustainable. The dyeability of the fabricated cotton sensors increased as the monomer concentration increased and the color change upon exposure to ammonia gas followed the same tendency. The fabricated cotton sensor prepared with the highest monomer concentration underwent a distinctive color change upon exposure to ammonia gas for 300 s (ΔE > 15). Furthermore, the cotton sensor exhibited remarkable durability to washing (wash fastness level: 5, ΔE maintenance rate after washing: ∼85 %) and rubbing (rubbing fastness level: 4/5, ΔE maintenance rate after rubbing: ∼95 %). Reusability testing of the fabricated cotton sensors showed that the halochromic property was retained after repeated washing (10 cycles). The results confirmed that the UV-induced photografting performance had been optimized and suggested that UV-induced photografting offered an eco-friendly alternative to conventional dyeing for the fabrication of halochromic textile sensors.

Wet synthesis of magnetically retrievable Mn/Nd co-doped cobalt ferrites for visible light-driven photocatalytic annihilation of azo dye

In this study, a surfactant assisted wet-chemical method was used to synthesize manganese and neodymium co-doped cobalt ferrite [Co1-xFe2-y O4 (x = Mn, y = Nd)]. The co-doping strategy was adopted to enhance the magnetic properties, tune the band gap, and hamper charge–recombination in the spinel ferrite during the photocatalytic application. Different dopant concentrations, namely Mn = Nd = 1.1 %, 2.2 %, 3.3 %, and, 4.4 %, were used to synthesize MNCF-1, MNCF-2, MNCF-3, and MNCF-4 samples, respectively. The pristine (CF) and co-doped samples (MNCF) were characterized via TGA, PXRD, Raman, FTIR, and UV/Vis techniques to examine the impact of co-doping on the various physicochemical and thermal properties. The optical study proposed the MNCF-4 sample with a band gap value of 2.88 eV as most suitable for visible-light harvesting. A dielectric study showed that co-doped ferrite with a higher dopant concentration (MNCF-4) exhibits boosted AC conductivity and substantially decreased leakage current as compared to the bare and co-doped samples. As the concentrations of the co-dopants increase, the coercivity field (Hc) decreases while the remanent magnetization (Mr) and saturation magnetization (Ms) increase. The MNCF-4 material exhibited the highest magnetic properties, ensuring its full and quick magnetic recovery at the completion of the photocatalytic process. In the context of photocatalytic applications, it was observed that the MNCF-4 catalyst exhibited a mineralization rate constant value of 0.016 min−1 for 92.5 % crystal violet (CV) dye. To mitigate the impact of dye sensitization, the photocatalytic efficiency of MNCF-4 material was assessed by using phenol as a representative colourless organic pollutant. The enhanced magnetic properties of the MNCF-4 catalyst enable its complete magnetic recovery and 90.2 % retention of the photocatalytic activities after five reusability tests.

Al-MIL-53 metal-organic framework supported Ru catalyst for selective hydrodeoxygenation of lignin-derived phenols into cyclohexane

Catalytic hydrodeoxygenation (HDO) of guaiacol, as a bio-oil model compound, was investigated employing Ru/Al-MIL −53 Metal-Organic Framework and Ru/γ-Al2O3 catalysts under external molecular hydrogen. Notably, the HDO results attributed the remarkable potential of the Ru/Al-MIL −53 MOF toward the comparatively high conversion of guaiacol (70%) together with a high proportion of cyclohexanol (23%) at a catalyst/feed (C/F) ratio of 1:5. However, only a 30% conversion was found with only 3.5% cyclohexanol for Ru/γ-Al2O3 for the same C/F ratio. This was due to the high porosity and presence of numerous vacancies in the MOF, which directly affects the H2-dissociation/ spillover that assists the transfer of produced H-radicals for further conversion of the adsorbed guaiacol molecules. Notably, the activity of Ru/Al-MIL −53 was remarkably increased by decreasing the amount of guaiacol. The maximum conversion was achieved (100%) for a C/F ratio of 1:1, with a higher (96.2%) selectivity for cyclohexane. The reusability test for the spent catalyst did not show any significant change in catalyst performance for up to five successive cycles.

Superhydrophilicity of photocatalytic branched TiO2 nanorods/In2S3 heterostructure for water purification

In2S3 / branched TiO2 nanorods (br-TiO2) heterostructure was prepared by a simple route using three-step methods as a visible and solar light photocatalyst for water treatment applications. Structural properties have been carried out by X-ray diffraction and Raman spectroscopy. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and atomic force microscopy has been used to determine the morphology and the surface roughness of samples. The In2S3/ br-TiO2 heterojunction confirm the presence of both structures of Rutile TiO2 and cubic β-In2S3. Optical results showed that the heterojunction exhibited increased absorption ability in the visible light, indicating an increased photoactivity for In2S3/ br-TiO2 in the visible light. Wettability studies reveal that In2S3/ br-TiO2 film is superhydrophilic with water contact angle of 0°. Photocatalytic activity of heterojunction In2S3/ br-TiO2 was assessed with remarkable degradability performance of 85% after 80 min under solar irradiation. The reusability test highlighted that the In2S3/ br-TiO2 still maintained high photocatalytic activity over five cycles. The photoelectrochemical activity was evaluated. The results showed the successful development of In2S3/ br-TiO2 heterostructure with better photoactivity properties. The In2S3/ br-TiO2 electrode achieved remarkably improved current density (0.59 mA.cm2 at 0.6 V vs Ag/AgCl) compared to br-TiO2 and In2S3.These results reveal that In2S3/ br-TiO2 thin films being excellent photoactivity along with its superhydrophilic nature which it is possesses great potential toward the development of newly synthesizable catalysts in the field of water purification.