A comparative study of Cu-impregnated ZnO and Ni-impregnated ZnO for the sonophotocatalytic degradation of cefixime in aqueous solution under visible light irradiation was carried out. Sonophotocatalysts were prepared by using a wet impregnation method and characterised using different spectroscopic techniques. Sonophotocatalytic efficiency of degradation is superior to photolysis, sonolysis, photocatalysis and sonocatalysis. Different operational parameters like pH, catalyst dosage, different enhancers, scavenger's effect, initial concentration of drug, reusability of catalyst and catalyst settling time were optimised. Optimum time of 30 min was found for the 45.7% degradation of cefixime using Cu-ZnO and 42.2% degradation using Ni-ZnO photocatalysts at pH 10. The degradation of cefixime increased from 75.3% to 100% with 5 mmol of hydrogen peroxide using 0.1 g/ L of Cu-ZnO and 99.8% using 0.15 g/L of Ni-ZnO, while other oxidising agents were found less effective using (Cu-ZnO-Ni-ZnO) photocatalyst. A very little decrease in degradation was observed with different types of scavengers. Catalyst reusability was checked up to three cycles and good results up to three cycles were achieved and followed pseudo-first-order kinetic model. Furthermore, the sonophotocatalytic activity was tested for real pharmaceutical wastewater resulting in 91 and 89% removal of total organic carbon (TOC) using (Cu-ZnO-Ni-ZnO), respectively. The proposed method was successfully applied on commercial and synthetic sample with satisfactory results.

In recent years, due to industrialization water pollution is the major issue. The aim of the present work was the synthesis of solid Gum Arabic Magnetized Graphene Oxide (GA-MGO) and its application for the removal of fluorescent dye, fluorescein from aqueous samples. The characterization of the composite was carried out through FTIR, SEM, EDX, point of zero charge, and surface area. Various parameters optimization such as pH, shaking time, adsorbent dose, adsorbate concentration, temperature, and their influence on the removal of fluorescein using GA-MGO composite during the adsorption process was studied. The synthesized GA-MGO exhibited high adsorption efficiency of 94.18 % in 60 mins (pH 2, fluorescein 20 µg mL-1, 0.08 g L-1 of adsorbent). The synthesized GA-MGO composite has a high capacity to remove fluorescein molecules from aqueous solution at 25 °C. The kinetics of adsorption was investigated and it was found that adsorption followed pseudo-second-order kinetics with the regression coefficient R2 value of 0.962. The R2 value of Langmuir (0.985) and Freundlich (0.894) showed that the Langmuir adsorption isotherm fitted best to the adsorption process. Different thermodynamic parameters, Gibb’s free energy and Van’t Hoff equation reveals tht the proposed reaction is spontaneous and exothermic. Regeneration of adsorbent/ desorption of dye and application of composite to the sample of sewage and industrial effluents results in better adsorption. The finding reveals the feasibility of GA-MGO composite as potential precursor for the effective adsorption of fluorescent dyes due to its high surface area.

BACKGROUND: Copper plays a leading role in the electronics industry. Drastic innovation and fast obsolescence rate raise the demand for copper for electrical and electronic equipment. The high amount of electronic waste discarded is considered the primary alternative source and is now seen as a secondary reservoir for copper metal. Besides the economic impact, copper interferes with selective recovery of other metals such as critical, precious and rare earth elements from electronic waste. RESULTS: In this work, to purify acid leach solution of electronic waste from Cu(II) ions, a selective sorbent was synthesized. A Cu(II) specified ligand, alpha-benzoinoxime, was impregnated with magnetic nanoparticle-modified activated carbon and utilized as magnetic solid-phase sorbent. The synthesized sorbent was analysed for its morphological and other characteristic properties. CONCLUSION: The study indicates that percent recovery increased from 89% to > 95% after impregnation. Complexation between Cu(II) and alpha-benzoinoxime-modified activated carbon caused the sorbent to attain higher retention at pH > 8.5. Sorption capacity calculated from Langmuir sorption isotherm was 147 mg g(-1), while the sorption process follows a pseudo-second-order kinetic model. The sorbed Cu(II) was quantitatively (> 97%) eluted with 1 mol L-1 nitric acid. The method was validated with standard reference material GF10928752-Aldrich. Results show that the synthesized sorbent is good for Cu(II) masking and recovery, even if applied to samples with a complex sample matrix. (c) 2022 Society of Chemical Industry (SCI).

Herbicides in wastewater are considered as a serious issue to environmental pollution. Different impregnated metal zinc oxide (Cu/ZnO and Ni/ZnO) as catalysts were prepared through wet impregnation method for the degradation of herbicides Isoproturon and triasulfuron. The prepared impregnated catalysts were characterized using scanning electron microscopy (SEM) and x-ray diffraction (XRD), energy dispersive x-ray (EDX) analysis, Fourier-transform infrared spectroscopyand surface area. The degradation of selected herbicides were investigated using combined effect of photocatalysis and sonication. The experimental parameters such as pH, irradiation time, photocatalyst dose, effect of oxidants, diverse ion effect, herbicide concentration and catalyst reusability have been optimized. The percent removal of isoproturon was found to be 99 and 98% at pH 7 and triasulfuron was 98% at pH 6 using Cu/ZnO and 99% at pH 7 using Ni/ZnO photocatalysts respectively. Graphical Abstract Graphical abstract of Ultrasound Assisted Photocatalytic Degradation of Isoproturon and Triasulfuron Herbicides

In the present work, alginate magnetic graphene oxide biocomposite was synthesized for the removal and extraction of aromatic amines (aniline, p-chloroaniline (PCA), and p-nitroaniline (PNA)) from water samples. The biocomposite was investigated for its physiochemical characteristics such as surface morphology, functional groups, phase determination, and elemental composition. The results revealed that the functional groups of graphene oxide and alginate retained in biocomposite with magnetic properties. The biocomposite was applied to water samples for the removal and extraction of aniline, p-chloroaniline, and p-nitroaniline through adsorption process. The adsorption process was studied under various experimental conditions like time, pH, concentration, dose, and temperature, and all the parameters were optimized. The maximum adsorption capacities at room temperature have an optimum pH = 4 for aniline = 18.39 mg g−1, for PCA = 17.13 mg g−1, and for PNA = 15.24 mg g−1. Kinetic and isotherm models showed that the experimental data is best fitted to pseudo-second-order kinetic model and the Langmuir isotherm model. Thermodynamic study suggested that the adsorption process is exothermic and spontaneous. Ethanol was found to be the best eluent for the extraction of all the three analytes suggested by the extraction study. The maximum percent recoveries from spiked water samples were calculated for aniline = 98.82

Dyestuffs are very persistent in nature and are present in large number in wastewater of different industries. The wastewater of different industries contains many pollutants which are hazardous for human health and environment. In the present study, sonophotocatalytic degradation of Acid red 17 (AR-17) dye in aqueous solution was investigated using silver impregnated zinc oxide (Ag/ZnO). Silver impregnated zinc oxide (Ag/ZnO) catalyst was prepared by wet impregnation method and characterized by SEM, EDX, XRD and band gap. Removal of dye was carried out at 40 kHz frequency ultrasound waves under visible light (Tungsten lamp) of 100 W. The effect of various operating conditions and reagents like H2O2 concentration, pH of the solution, amount of catalyst and concentration of AR-17 dye were investigated. At the own pH of dye using 7 mmole H2O2 concentration 92.9 % degradation of acid red 17 was observed. The degradation increased with increase in irradiation and sonication time of 30 minutes and with 0.25 g /100 mL Ag/ZnO highest degradation 92.94 % was found. The TOC analysis was also carried out sonophotocatalytically and 80 % removal of total organic compounds was observed. The degradation of AR-17 followed pseudo-second-order kinetics with high value of correlation coefficient.

Magnetic chitosan (MC) was used as an ecofriendly and potential adsorbent for the removal of bisphenol-A and 4-tert-butylphenol from water samples. The magnetic chitosan was synthesized and characterized for functional groups, surface morphology, elemental composition, and crystallinity using spectroscopic techniques. Factors influencing the uptake such as pH, mass of adsorbent, bisphenol-A and 4-tert-butylphenol concentration, contact time, and temperature were examined thoroughly using aqueous solutions. Equilibrium, kinetic, and thermodynamic parameters were evaluated, and the results revealed that the adsorption of bisphenol-A and 4-tert-butylphenol followed pseudo-second-order kinetics and Langmuir adsorption isotherm. The adsorption processes were exothermic and spontaneous. The method was found feasible for the removal and extraction of bisphenol-A and 4-tert-butylphenol in environmental water samples. The recovery of bisphenol A and 4-tert-butylphenol in tap water ranged from 95.6% to 96.8% and 95.4% to 101.2% and in river water from 87.6% to 95.9% and 92.8% to 98.2%, respectively. The results indicate that magnetic chitosan is a potential adsorbent for easy, effective removal and extraction of bisphenol-A and 4-tert-butylphenol from environmental water samples, and the adsorbent material is chemically benign and environment friendly.

A comparative study of Cu-impregnated ZnO and Ag-impregnated ZnO for the sonophotocatalytic degradation of cefpodoxime proxetil in aqueous solution under visible light irradiation were carried out. Optimum conditions for degradation of cefpodoxime proxetil using Cu-ZnO and Ag-ZnO was investigated. The effect of enhancers and scavengers were investigated using optimum conditions and hydrogen peroxide as enhancers. 100% degradation was achieved using Cu-ZnO and Ag-ZnO. Furthermore, total organic carbon analysis was carried out and 89% using Cu-ZnO and 93% using Ag-ZnO removal of total organic compounds were observed. The sonophotocatalytic degradation of cefpodoxime proxetil using Cu-ZnO and Ag-ZnO followed pseudo-first-order kinetic and the rate of degradation of cefpodoxime proxetil using Ag-ZnO was found higher (k(1) = 0.228) than the Cu-ZnO photocatalyst (k(1) = 0.185). The method has also been successfully applied in samples for sonophotocatalytic degradation.

Scarcity in mining and geo-political direction diverts attention toward critical metal recycling. Gallium (Ga), indium (In) and germanium (Ge) are among the critical metals that consume approximately 80

An eco-friendly efficient supramolecular solvent-based method was developed for extraction and determination of selected non-steroidal anti-inflammatory drugs (NSAIDs) such as diclofenac sodium, caffeine and paracetamol in water samples followed by detection with high-performance liquid chromatography. Supramolecular solvent (SUPRAs) with composition of 400 mu L of 1-undecanol as reverse micelles in dispersing solvent of 15% tetrahydrofuran (THF) solution in water at pH 4 used as extracting solvent for selected NSAIDs. Various factors affecting the extraction efficiency of NSAIDs like amount of 1-undecanol, percentage of THF, composition of SUPRA, pH, vortex time and sample amount were studied. Limit of detection (S/N = 3) and quantification (S/N = 10) were 0.02 and 0.08 mu g mL(-1) for paracetamol, 0.006 and 0.02 mu g mL(-1) for caffeine, 0.06 and 0.2 mu g mL(-1) for diclofenac sodium with linear range of 0.1-12 mu g mL(-1). The inter-day relative standard deviation (RSD) values were 3.1%-5.2%, 3.3%-4.2% and 2.2%-3.6%, while for intra-day the RSD values obtained were 2.4%-4.1%, 1.4%-3.1% and 1.5%-4.1% for paracetamol, caffeine and diclofenac sodium, respectively. The proposed method has been applied successfully to the spiked water samples and recoveries were found in the range of 89.5%-94.6% for tape water, 88.5%-92.8% for canal water and 90.0%-95.2% for industrial wastewater samples was obtained.

Metal content present in the spent lithium ion batteries (LIBs) make their recycling vital for resources conservation and environmental sustainability. Cobalt, grouped among critical, valuable and strategic metals, is the basic part of the LIBs cathode and defines its recycling economic capacity. In the present work, an attempt has been made to develop an efficient hydrometallurgical technique based on solid phase extraction method for the recovery of cobalt from leach solution of waste LIBs. An adsorbent was synthesized by diazotization of p-phenylenediamine modified graphene oxide (GO-PPDA) sheets with disodium 1-nitroso-2-naphthol-3-6-disulphonate (nitroso R-salt, NRS) in one pot process of Mill's reaction. Maximum retention of cobalt (99.9%) was achieved at pH 5.5-6.5. Adsorption kinetics favour complexation as a separation mechanism following second order kinetics model with R-2 value of 0.9999 with sample flow rate of 1.5 mL/min. Langmuir isothermal model (R-2 = 0.998) also confirm monolayer chemisorption mechanism with 29.7 mg/g adsorption capacity. The two-step elution mechanism enables us to achieve 99.5% extraction efficiency with similar to 98% purity. The chelating adsorbent was found reasonably stable even after the 30th cycle of adsorption and desorption with <2% decrease in removal efficiency. The results show that the proposed adsorbent is successful in terms of selectivity, reusability, analytical merit and stability.

Liquid-liquid microextraction method based on supramolecular solvent was proposed for analysis of dinitroaniline herbicides (pendimethalin and trifluralin) residue in water and onion samples. In the present method, reverse micelles of undecanol (250 mg 1-undecanol) dispersed in tetrahydrofuran and water was used as supramolecular solvent. The parameters affecting the extraction efficiency of herbicides like pH, amount of 1-undecanol, percentage of tetrahydrofuran (THF), composition, volume of supramolecular solvent and vortex time were studied. At optimum conditions, the linear range for both herbicides was from 0.03 to 100 mgL(-1). The method was found selective for determination of dinitroaniline herbicides in the presence of coextractants of onion samples. The percentage recoveries were found 97.5-100% and 91.2-95.2% for water and onion samples, respectively. Limit of detection (S/N = 3) of pendimethalin and trifluralin was in the range of 3.0-5.5 mu gL(-1) for water samples and 7-11 mu gL(-1) for onion samples. Preconcentration factor was found to be 63. Calculated analytical eco-scale value (>75) for the proposed method fulfilling principles of green analytical chemistry.

In this study, fuller's earth (FE) modified with sodium dodecylbenzene sulphonic acid was used for adsorptive removal of fenoxaprop-p-ethyl (FPE) herbicide from water samples and statistical validation of the experimental observations was accomplished. All the adsorption experiments were conducted in batch mode. The effect of pH, agitation time, adsorbent dose and initial herbicide concentration on adsorption process was studied. About 98.5% adsorption efficiency was achieved at initial analyte concentration of 1000 mg L-1 at pH 6 within 60 min at adsorbent dose of 0.1 g. The adsorption kinetics were studied and pseudo-second-order kinetic model was found to follow the adsorption kinetics with R-2=0.998. The isotherm studies show that the adsorption data fit well to the Freundlich isotherms. In statistical evaluation, the individual as well as the interaction effect of various factors on adsorption was investigated and it was found that concentration, pH and adsorbent dose are the significant factors with p values of 0.0001, 0.004 and 0.006 respectively, while contact time was found statistically insignificant having p value greater than 0.05. The coefficient of determination (R-2=0.930) shows that % adsorption is highly dependent on the studied factors and their interactions. Under the optimized set of conditions, high absorption capacity of 200.22 mg g(-1) was achieved.

In the present study, magnetic graphene oxide assimilated magnetic silica polyaniline (Fe3O4@SiO2@PANI-GO) was synthesized using co-precipitation, oxidative polymerization and modified Hummer’s method for Fe3O4, PANI and GO preparation. The resultant adsorbent was characterized using SEM, EDX and FTIR. The structure of the composite has high affinity for the aromatic compounds due to π–π interaction, n-π interaction and hydrogen bonding. Therefore, the composite was investigated for the removal of bisphenol-A from water samples with magnetic solid phase extraction. The effect of parameters such as solution pH (2–10), amount of adsorbent (10–120 mg), time (10–300 min), temperature (20–100 °C) and bisphenol-A concentration (25–750 µg/mL) were studied. At optimum conditions, the composite showed good Langmuir adsorption capacity (454.56 mg/g) and the adsorption process followed pseudo-second-order-kinetic model. Thermodynamic parameters ΔG° was negative, suggested that the adsorption process was spontaneous, exothermic (ΔH° = − 13.3 kJ/mol) and diffusion controlled (Ea = − 13.03 kJ/mol). The stability and reusability of the proposed adsorbent was checked with successive adsorption and desorption cycles and the results demonstrated that the composite had great potential for the adsorption of bisphenol-A from environmental water for treatment of wastewater.

Waste electrical and electronic equipment (WEEE) are considered as a major source for both virtuous and hazardous metals. Hazardous metals make their way to cause pollution of soil and water. The risk of contamination is very high where WEEE is being processed. In the present study activated carbon was synthesized from sawdust and modified with 1-(2-pyridylazo)-2-naphthol (PAN) through diazotization. The surface modification was confirmed through various instrumental analysis like CHNO elemental analyzer, FTIR, TGA/DSC, BET, SEM and EDX. Surface area of activated carbon calculated using BET method was 178 m(2)/g with average pore size of 14.5 (angstrom) however, surface area gets reduce to 68 m(2)/g after surface modification. The synthesized adsorbent was packed in a column and used for extraction of cadmium, lead and nickel from WEEE and some soil samples. Different analytical parameters like pH, sample volume and flow rate, eluent type and flow rate, effect of coexisting ions and initial concentration were optimized. It was observed that the adsorbent has high retention factor (> 94%) for the selected metal ions at neutral pH with 12 mL/min sample flow rate. Nitric acid solution (5 mol/L) of 7 mL was found suitable for quantitative elution with flow rate of 2 mL/min. The method was efficient even with higher sample volume of 1000 mL, 1200 mL and 900 mL with enrichment factor of 143, 171 and 129 for Cd, Pb and Ni, respectively. As compared to batch adsorption, cartridge of the synthesized adsorbent can be regenerated and used multiple times with ease. Similarly, it also prevents both loss of adsorbent and collected metals ions as normally in case of filtration or centrifugation process.

Borax and its calcined derivatives were used in pyrolytic valorization of tire tube rubber to produce high value oil and gases. This work involved the preparation and characterization of catalysts and optimization of the reaction parameters for the catalytic and non-catalytic pyrolysis of waste tire tube rubber. The derivatives of borax catalyst were prepared by calcining it at 600 °C, 800 °C and 1000 °C. The borax derivatives were labeled as borax-600, borax-800 and borax-1000 and used for the pyrolysis of waste rubber. The outcomes of the catalytic and thermal pyrolysis processes were compared to check the effectiveness of the borax derivatives as a catalyst. Both processes produced different quantities of oil, gas and char specifically in case of borax catalyzed and borax-1000 catalyzed reactions. The oil product of thermal pyrolysis was composed of 15 compounds while borax catalyzed pyrolysis produced oil with 14 compounds. On the other hand, all borax derivatives produced oil having nine compounds. The oil contained aliphatic and cyclic hydrocarbons along with small quantities of sulfur and phosphorous containing organic compounds. The results of distillation showed that thermal pyrolysis produced 83.80% volatile oil while borax catalyzed pyrolysis produced 83.84% volatile oil. The oil content decreased to 66.34% with an increase in borax calcination temperature. Similarly, thermal pyrolysis produced 12.56% residue while borax catalyzed reaction produced 16.10% residue. The residue decreased slightly with a rise in calcination temperature.

Borax catalyst was used to pyrolyze and copyrolyze the waste polyethylene and tire tube rubber into combustible oil and gas. The borax catalyst not only acted as a solid base but also offered empty orbitals to cleavage the bonds of polymeric feedstock and secondary cracking reactions. The pyrolysis reactions were carried out in a custom-made steel reactor placed in a top load furnace equipped with digital temperature controller. Both polymeric wastes were pyrolyzed separately and by combining in different ratios with and without using borax catalyst. The effect of reaction temperature and time on quality and quantity of liquid and gaseous products was investigated in the range of 200 degrees C to 600 degrees C and 15-75 min, respectively. In noncatalytic pyrolysis, the pure and copyrolyzed polyethylene with rubber yielded maximum oil at 500 degrees C and 600 degrees C, respectively. In borax-catalyzed pyrolysis, the pure polyethylene and copyrolyzed with rubber yielded maximum oil at 400 degrees C and 500 degrees C, respectively. Notable difference in product fractions of conventionally pyrolyzed and borax-catalyzed pyrolysis was evident at all process temperatures. The chemical nature of oil was checked using GC-MS, while gaseous product was analyzed using glass vessel traps containing different chemical reagents. The combustibility of gaseous product was also checked using a miniature Bunsen burner.

Orange peel powder was impregnated with magnetic nanoparticles through co-precipitation with Fe 3O 4 nanoparticles and used for the removal of Ni(II) from aqueous solutions. The adsorbent magnetic nanoparticles orange peel powder (MNP- OPP) was characterized by Fourier-transform infrared spectroscopy for surface functional group and scanning electron microscope for the surface morphology. The effectiveness of Ni(II) removal was studied systematically as a function of solution pH 2-7, amount of adsorbent 20-220 mg, contact time 20-60 min, initial metal ion concentration 200-120 mg L-1 and temperature 303-363 K. Maximum uptake of Ni(II) ( 98.12%) was observed at pH 7 with 60 min agitation time. The kinetic studies showed that the data followed second-order kinetics with a correlation coefficient of 0.9948. Adsorption isotherms show that the data fitted to Langmuir adsorption isotherm (R-2 = 0.9954) with the monolayer adsorption capacity (Q(0)) of 110.12 mg g(-1). The thermodynamic study revealed that the adsorption of Ni(II) ions onto the MNP-OPP composite was spontaneous and endothermic. The effect of different coexisting ions like alkali, alkaline earth metals and transition metals was studied and the results revealed that orange peel with magnetic nanoparticle composite can be used for removal of Ni(II) from water samples as an alternative adsorbent. The method was successfully applied to real environmental water like tap water, canal water and river water with quantitative % adsorption results.

The visible-light-induced semiconductor photocatalyst nickel (Ni) impregnated ZnO was prepared by the wet impregnation method. Impregnation of Ni on ZnO shifts the bandgap from UV to the visible region. The present study involves the sonophotocatalytic degradation of textile dyes Acid Violet 49 (AV-49) and Acid Blue 45 (AB-45) in the presence of Ni-ZnO photocatalyst under the irradiation of visible light. The degradation efficiency of sonophotocatalysis was higher than sonolysis, sonocatalysis, photolysis and photocatalysis. The photocatalyst was characterized by scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. Effect of different operational parameters such as pH, catalyst dosage, oxidizing agents (enhancers), initial dye concentration, scavengers, catalyst re-usability, catalyst settling time and catalyst poisoning were studied. Maximum degradation (100%) of AV-49 and AB-45 was found at pH 10 in 20 min. The re-usability of the photocatalyst test showed an increase in time of degradation from 20 to 60 min with a 10%-20% decrease in degradation efficiency. The degradation of AV-49 and AB-45 follows the pseudo-first-order kinetic model. The results of sonophotocatalytic degradation of textile dyes were attributed to the efficient absorption of visible light, separation of charge carriers and good surface area. The method of sonophotocatalytic degradation assisted with the oxidizing agents has also advantages like safety, high efficiency and economy if applied to the textile dye wastewater treatment.

In the proposed method iron crosslinked alginate encapsulated magnetic graphene oxide beads were synthesized and used as an adsorbent for the microextraction of endocrine disrupting compounds from water samples and further analyzed by high performance liquid chromatography with ultraviolet detector. The beads were characterized using spectroscopic techniques, such as Fourier transform infra-red spectroscopy for the determination of different functional groups, Scanning electron microscopy for surface morphology, X-ray diffraction for phase determination and energy dispersive X ray spectroscopy for elemental composition. The results revealed that beads surface have functional groups of alginate and graphene oxide which are involved in pi-pi, n-pi interactions and hydrogen bonding for the bisphenol A and epichlorohydrin adsorption. The experimental conditions were studied for two endocrine disrupting compounds (Epichlorohydrin ad Bisphenol A) and at optimum conditions the adsorption capacity was 6.73 mgg(-1) for epichlorohydrin and 7.01 mgg(-1) for bisphenol A. The kinetic and equilibrium studies revealed that the adsorption process follow pseudo-second order kinetics and Langmuir equilibrium models. Analytical parameters were calculated for the microextraction of epichlorohydrin and bisphenol A. Limit of detection was 8.25 ngL(-1) and 13.99 ngL(-1) (n = 4) for epichlorohydrin and bisphenol A, respectively. Different solvents used for microextraction and maximum extraction of both endocrine disrupting compounds were obtained with methanol. The proposed method was applied to spiked samples and the recovery values were 97.17 +/- 3.13% for epichlorohydrin and 99.46 +/- 1.39% for bisphenol A. The magnetic graphene oxide encapsulated inside an alginate shows nontoxic green chemical with high extraction performance for toxic organic compounds in water treatment.