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In this study, an effective and novel nanocomposite (Fe 3 O 4 @TAS) was prepared and applied for the removal of Cd(II), Cr(III) and Co(II) from liquid medium. The mechanism for the adsorption was elucidated by investigating the adsorption kinetics, isotherms and thermodynamics, thoroughly. The maximum adsorption capacities as found by the Langmuir model were 286, 370 and 270 mg g −1 for Cd(II), Cr(III) and Co(II), respectively. The structure, size, porosity and magnetic property, of the prepared magnetic nanocomposite were investigated by FT-IR, XPS, SEM-EDX, BET, XRD, HRTEM and VSM analyses. The saturation magnetization and BET surface area for Fe 3 O 4 @TAS were 41.4 emu g −1 and 210.34 m 2 g −1 , respectively. Fe 3 O 4 @TAS was easily separated from aqueous solution using external magnet and it was regenerated by simple washing with 0.01 M HCl solution. The thermodynamic parameters showed that the involved process was spontaneous and exothermic. The findings inferred that Fe 3 O 4 @TAS had the efficiency in treating wastewater with coexisting metals such as Cd(II), Cr(III) and Co(II) metal ions. [ABSTRACT FROM AUTHOR]

Healthy environment is necessary for growth and development of every living being. The deterioration of ecosystems due to discharge of inorganic and organic pollutants from different industries is one of the major problems. The major impact of these sources has been on our water resources. The literature studies revealed that from the age's humans are using various natural and synthetic materials for water purification. With Gradual development, these materials are modified and newer alternative materials are searched and fabricated. The present study relates to fabrication of novel Gum arabic-crosslinked-poly(acrylamide)/Ni(OH) 2 /FeOOH nanocomposite hydrogel (GA-cl-poly(AAm)/Ni(OH) 2 /FeOOH NCH) using simple copolymerization technique. The structural analysis of GA-cl-poly(AAm)/Ni(OH) 2 /FeOOH NCH was performed by employing diverse modern analytical instrumentations such as transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The HRTEM and SEM micrographs clearly demonstrated the engulfment of Ni(OH) 2 and FeOOH particles within the nanohydrogel matrix. The photocatalytic performance of synthesized GA- cl -poly(AAm)/Ni(OH) 2 /FeOOH NCH was investigated for photodegradation of methylene blue dye. All the parameters such as contact time, pH, concentration of methylene blue, NCH dosage and concentration of H 2 O 2 were optimized. It was noted that 75% methylene blue was degraded at optimized condition using GA- cl -poly(AAm)/Ni(OH) 2 /FeOOH NCH in presence of H 2 O 2. Image 1056 • Gum Arabic-crosslinked-poly(acrylamide)/Ni(OH) 2 /FeOOH nanocomposite hydrogel was synthesized using copolymerization technique. • This nanocomposite hydrogel was used for the photodegradation of Methylene blue dye. • 75% methylene blue dye was degraded at optimized condition. • Efficient photocatalytic activity was observed even after 5 successive reuse. [ABSTRACT FROM AUTHOR]

Abstract In this study, the adsorption of methylene-blue (MB) and Cd(II) onto low cost material and easy separation towards cleaner environment was investigated. The cobalt ferrite embedded nitrogen doped carbon nanocomposite (CF@NC) was fabricated using albumen protein bi-metals complexes. The prepared nanocomposite was characterized using several analytical techniques. The electron microscopy results revealed that nanoparticles were spherical in the size range between 10 and 20 nm. The results of Brunauer–Emmett–Teller revealed that the fabricated nanocomposite (CF@NC) had porous nature and the surface area of this nanocomposite was found to be 691.82 m2g−1. The surface of CF@NC adsorbent had a negative charge, a value of about −27.5 mV determined by zeta potential measurement. The adsorption studies were carried out using different parameters such as pH, concentration of the pollutants, adsorption time and temperature for the adsorption of both pollutants. The adsorption kinetics supported the pseudo-second-order reaction and the adsorption isotherm supported the Langmuir isotherm models. The maximum adsorption capacity for Cd(II) and MB was estimated to be 245.09 mg g−1 and 421.94 mg g− 1. The results concluded that the prepared nanocomposite was a promising hybrid nanocomposites for the rapid adsorption of Cd(II) and MB from water. Graphical abstract Image 1 Highlights • Synthesis of cobalt ferrite embedded nitrogen doped carbon nanocomposite (CF@NC) using egg albumen. • The CF@NC nanocomposite showed the high rates of adsorption for Cd(II) and MB dye. • The adsorption was endothermic for both Cd(II) and MB dye. • The CF@NC was regenerated by simply washing with 0.1 M methanol solution. [ABSTRACT FROM AUTHOR]

Iron nanoparticles (Fe NPs), monometallic Fe@carbon quantum dots (Fe@CQDs) and bimetallic Fe/Ag@carbon quantum dots (Fe/Ag@CQDs) nanocomposites were prepared by simple co-precipitation/reduction method. The nanoparticles (NPs), monometallic nanocomposite (MNCs) and bimetallic nanocomposite (BMNCs) were characterized using various techniques. The adsorptional/photocatalytic activity of NPs, MNCs, and BMNCs were investigated for the removal of fast green (FG) dye from aqueous medium. The degradation of FG dye under combined adsorptional/photocatalytic condition was efficient. The catalytic nature of synthesized NPs, MNCs and BMNCs was also explored for the oxidation of benzyl alcohol and esterification of acetic acid. For oxidation of benzyl alcohol with H 2 O 2 in the presence of acetonitrile (ratio of butyl alcohol: H 2 O 2 was 2:1) at temperature 80 °C, the Fe NPs gave maximum yield (87%). The esterification of acetic acid with ethyl, isopropyl and butyl alcohol showed that butyl alcohol gave maximum yield of 82%, 80%, and 84% for Fe NPs, Fe@CQDs MNCs and Fe/Ag@CQDs BMNCs, respectively. [ABSTRACT FROM AUTHOR]

Currently, the photocatalytic nanomaterials performing under solar radiation have gained worldwide attentions due to increasing environmental deterioration. For utilizing the sunlight for degradation of emerging pollutants it is important to develop visible active photocatalysts. This laboratory scale work reports magnetic and optically active nano-photocatalyst Fe x Zn 1−x O(x = 0.01, 0.03, 0.05) synthesized by solution combustion method. High resolution transmission microscopy suggests a slight degradation in the crystallite structure with Fe doping. X-ray photoelectron spectroscopy analysis shows the presence of intrinsic defects in the crystal structure. Zn resides in +2 and and Fe in +3 oxidation state. Optical band gap studies were made with band structure for each doped sample. The photoctalytic activity of the samples was tested by solar degradation of noxious pollutant Bisphenol A. 99.1% of bisphenol was degraded in 90min in presence of Fe 0.03 Zn 0.97 O under synergistic adsorption and photocatalysis. The results were analyzed in terms of total organic carbon, chemical oxygen demand, effect of scavengers, gas chromatography-mass spectrometry and reusability. In presence of Fe 0.03 Zn 0.97 O, 45.3% of total organic carbon was removed and chemical oxygen demand was reduced to 11.2%. A possible mechanism with structures of the intermediates has been given. Effect of scavengers reveal that hydroxyl radicals are major reactive oxygen species involved which is also supported by the band edge positions. The research work promises to design highly photo-active tuneable magnetic photocatalysts for solar powered degradation of contaminants of emerging concern with a simple and cost-effective approach. [ABSTRACT FROM AUTHOR]

Over 100 million tons of cotton waste are produced annually, representing 35–40% of global textile waste. However, less than 30% of cotton waste is recycled annually. In particular, the fibers less than 7 mm in length dropped during the opening and carding process of cotton waste fabrics have not found a mature utilization method. This work demonstrates and reveals a strategy to transform short cotton fibers into a renewable cellulose fiber self-reinforcing composite paper (CCP). Recycled cotton staple fibers less than 3 mm were prepared into CNFs by TEMPO oxidation. The use of recycled cotton fiber (3–7 mm) as reinforcement and CNFs as a matrix results in a composite material bonded through hydrogen bonding. The recovered cotton fibers and CNFs soliquoid combine together to form a paper pulp, which is then transformed into CCP using wet-laid webs and hot-pressing techniques. When the CNF content reached 5%, the tensile strength of CCP was 86.68 MPa, which is 1.8 times that of the commercial A4 paper. The tensile strength of the CCP only decreases by 25% from the dry state to the wet state, while that of A4 paper after soaking water is almost zero. This makes CCP a special paper with broad application prospects. Since CNF extracted from cotton waste textiles is used as a strengthening agent and without any chemical adhesives added in the paper-making process, which makes the production process of CCP cleaner and can be recycled in a closed loop. Overall, the promising strategy achieves at least four objectives related to cleaner production: maximum recycling of cotton waste, CNF instead of traditional chemical adhesives used in paper-making, water recovery (internal recycling), and realising closed-loop recycling. This technology can potentially be applied to a wide range of colored papers and intelligent packaging papers in the future. [Display omitted] • Cellulose nanofibers extracted from cotton waste were used as an adhesive in papermaking. • A cellulose fiber self-reinforcing composite paper was prepared from cotton waste. • The cellulose composite paper has excellent mechanical strength and water stability. • The cellulose composite paper can be easily recycled with a prolonged life cycle. [ABSTRACT FROM AUTHOR]

4-Nitrophenol (4-NP) has become anthropogenic pollutant and poses a threat to the environment and human health. The fast detection and reduction of 4-NP can reduced their environmental and health issues. In this study, we have prepared the spherical shaped gold nanoparticles (AuNPs) decorated multi-walled carbon nanotubes (MWCNTs) in the hydrogel matrix. The prepared nanocomposite (Au@MWCNTs) was characterized successfully by several analytical techniques such as FTIR, Ramman, UV–visible spectra, XRD, XPS, and TEM. The surface of MWCNTs was decorated with AuNPs with the diameters range between 10 and 35 nm, the HRTEM results show 2.36 Å interlayer spacing corresponding to (111) crystal planes. The prepared nanocomposite was used as an electrochemical detector in the detection of 4-nitrophenol (4-NP). A large reduction peak was observed at −0.56 V corresponding to the reduction of 4-NP toward p-hydroxyaminophenol using 4 e − processes, additionally two peaks were observed at 0.13 V and 0.19 V corresponding to the redox behavior p-hydroxyaminophenol and p-nitrosophenol. It was clearly observed, that the Au@MWCNts electrode detects at low concentration range with high sensitivity. Moreover, Au@MWCNTs was also used as a catalyst for the reduction 4-NP to 4-AP (4-aminophenol) using NaBH 4 via pseudo-first-order and the rate constant was found to be 4.9 × 10 −3  s −1 supporting the promising reduction of 4-NP. [ABSTRACT FROM AUTHOR]

Among the heavy metals, lead is one of the toxic metals which is being released into the environment through various anthropogenic sources and they are of serious threat to the ecosystem. Hence in this study, we have made efforts to utilize bacteria for the removal of lead. The lead resistant bacterial strain namely, Ralstonia solanacearum KTSMBNL 13 was isolated from heavy metal polluted electroplating industrial soil. Factors affecting the removal of lead namely, initial lead ion concentration, solution pH, temperature and contact time were investigated. Results showed that maximum removal of lead was attained (90%) at an initial pH value of 6.0, temperature of 35 °C and contact time of 26 h with an initial metal concentration of 100 mg L −1 . In order to identify the functional groups involved in the uptake of lead ions, FTIR, SEM–EDX, TEM and XRD analysis were carried out. Also the antibiotic sensitivity test for Ralstonia solanacearum KTSMBNL 13 was carried out and it was found that the isolate was sensitive to gentamicin, streptomycin and tobaramycin among the tested 12 antibiotics. From the outcome of the results, it has been demonstrated that Ralstonia solanacearum KTSMBNL 13 is a novel bacteria which can be used as an alternative and promising candidate and can be applied to remove lead from various metal contaminated sites. [ABSTRACT FROM AUTHOR]

In this research work we report synthesis of g-C 3 N 4 /FeVO 4 (CI) and g-C 3 N 4 /FeVO 4 /Fe@NH 2 -Biochar (CIB) nano-hetero assemblies for removal of methyl paraben (MeP) and 2-cholrophenol (2-CP) via adsorption, photocatalysis and photo-ozonation. CI and CIB have been characterized by FT-IR, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–Vis spectroscopy, photoluminescence (PL), vibrating sample magnetometry (VSM), Brauner-Emmet Teller surface area analyzer (BET). CIB shows good photocatalytic activity owing to higher specific area, nanosheet porous structure, stability, broader solar spectrum response and reduced charge carriers recombination. Fe@NH 2 -biochar facilitates the degradation via high adsorption capability due to reduced recombination, better charge separation, adsorption and acting of biochar as sink of electrons. The CIB photocatalytic system was tested under three experimental conditions for photodegradation of MeP and 2-CP; adsorption followed by photo-degradation (AP); simultaneous adsorption and photocatalysis (SAP); SAP + O 3 . An apparent synergism between adsorption, photocatalysis and photo-ozonation brings out excellent and promising results. 98.4% of MeP and 90.7% of CP degradation was achieved under simultaneous adsorption and photocatalysis in presence of CIB. The results were analyzed in terms of reaction kinetics, adsorption isotherms, scavenger effect, liquid chromatography-mass spectrometry (LC-MS), Total Organic Carbon (TOC) analysis and cytotoxicity analysis of treated water. An efficient TOC removal 74.2 & 73.9% for MeP and 2-CP were respectively achieved under SAP + O 3 +CIB photocatalysis system. Degradation pathways have been proposed for degradation of MeP and CP thorough photo-degradation and photo-ozonation. The cyto-toxicity studies on Human peripheral blood lymphocytes provide a reference for removal of noxious pollutants in real systems. This experimental work paves a way to design tuneable simple junctions for photocatalytic applications by utilizing various experimental protocols. [ABSTRACT FROM AUTHOR]

In this study, desorption of Methylene blue (MB) dye from brown macroalga, Nizamuddinia zanardinii was investigated. Batch experiments were conducted to determine the effects of various operating parameters namely, the effect of seventeen different eluents, eluents concentrations, dye saturated alga weight, different HCl:1-butanol ratios, different particle sizes, different alga mass washing modes (after sorption experiment), initial dye concentration in the sorption experiment and contact time on the desorption efficiency of MB dye from brown macroalga. Among the seventeen eluents tested, hydrochloric acid (HCl) was found to be the most effective eluent for dye desorption. The mixture of 1 M HCl (25%):1 M 1-butanol (75%) was found to increase the dye desorption efficiency up to 63.67 ± 1.67%. Dye desorption percentage increased by increasing the alga particle sizes from <75 μm to >250 μm. The highest and lowest desorption efficiencies were attained by wet and dry masses after water washing by shaker, respectively. Both isotherm and kinetic data were obtained and fitted very well with the Sips isotherm model and pseudo-second-order kinetic model. After five sorption/desorption cycles, the dye sorption efficiency decreased from 96.99 ± 0.90% to 48.16 ± 1.98%, and the dye desorption efficiency decreased from 68.70 ± 2.03% to 46.83 ± 1.49%. Overall, this study has demonstrated that brown macroalga is a promising sorbent for the removal of MB dye from aqueous solutions. [ABSTRACT FROM AUTHOR]

A predictive model is developed using an artificial neural network (ANN) to calculate the solid-liquid, and gas yields (wt %) from the torrefaction of olives stones, based on the material and process parameters. These parameters are average olive stone particle size, reaction temperature and reaction time. Ordinary Kriging interpolation is coupled with ANN to improve the experimental data resolution by increasing the data points used in building the ANN models. This coupling improved the ANN prediction accuracy (R2) by 11.1%, 13.5%, and 1.0% in training and 27.3%, 8.5%, and 14.8% in validation of the solid, liquid and gas yields, respectively. Also, the mean absolute deviations of the models significantly improved after the coupling. The prediction profiles show a linear relationship between the solid and liquid yields and a nonlinear relation for the gas yields in terms of the material and process parameters. Average olive stone particle size showed the highest effect on the yields due to the improvement in heat transfer with the exposed surface area of the olive stones leading to a faster reaction rate. • Ordinary Kriging interpolation was coupled with Artificial Neural Network. • The average particle size, reaction temperature and time were investigated. • By increasing temperature, the solid yield decreased while the liquid and gas yields increased. • The prediction profiles show a linear relation between the solid and liquid yields. • Average olive stone particle size showed the highest effect on the yields. [ABSTRACT FROM AUTHOR]

Solar-light powered environmental detoxification is surely a promising and sustainable approach for common goals of human development and ecosystem preservation. Focussing on this, we herein report fabrication of a novel solar active heterojunction Fe 3 O 4 @SrTiO 3 /Bi 4 O 5 I 2 an in-situ hydrothermal route. The heterojunction was used for the degradation and mineralization of anti-inflammatory drug Diclofenac (DCF) as target pollutant under simulated solar-light irradiation. Current results reveal that the optimized junction displayed 98.4% diclofenac removal in 90 min with 87.2% mineralization. The ESR probe suggests that both ●OH and ●O 2 − radicals are active species involved in DCF degradation. Analysing the band structure, thermodynamic feasibility and the photocatalytic performance, a traditional mechanism was ruled out and a Z-scheme transfer was predicted. The charge separation was obviously drastically improved by the Z-scheme transfer and facilitation by Fe 3 O 4 and Ti4+/Ti3+ in-built redox mediator. A degradation route was predicted on basis of intermediates detected by liquid-chromatography mass spectrometry analysis. This work promises to provide future possibilities for rational designing and fabrications of semiconductor heterojunctions for solar environmental applications. [Display omitted] • Solar active Fe 3 O 4 @SrTiO 3 /Bi 4 O 5 I 2 heterojunction formed by in-situ hydrothermal route. • High performance removal of diclofenac under simulated solar light. • Low recombination, high charge transfer capacity and photocurrent response. • Fe 3 O 4 and Ti4+/Ti3+ in-built redox for facile Z-scheme transfer. • ●OH and ●O 2 − radicals are both active species-High magnetic separation [ABSTRACT FROM AUTHOR]

Capacitive deionization (CDI) is one of the most efficient and emerging techniques for water desalination applications. This work reports the development, characterization and CDI studies of watermelon derived activated carbon (WMAC) and its MnFe 2 O 4 composite (WMAC/MnFe 2 O 4) for NaCl desalination. WMAC was prepared through single-step low-temperature pyrolysis by H 3 PO 4 activation. Facile synthesis of spinel MnFe 2 O 4 nanoparticles on WMAC surface was performed through the hydrothermal technique. Morphological, textural and physico/electro–chemical analysis showed the effect of MnFe 2 O 4 incorporation on WMAC. The nanocomposite possessed definite crystallites, low structural disorders and sufficient magnetization for electrochemical applications. Also, the nanocomposite was dominantly composed of mesopores with a specific surface area of 483 m2/g. The high specific capacitance value of 425 F/g (scan rate – 10 mV/s) along with better stability and low charge resistance, confirmed the suitability of WMAC/MnFe 2 O 4 as an efficient electrode material for CDI applications. NaCl removal studies using WMAC/MnFe 2 O 4 showed an electrosorption capacity of 29.7 mg/g for the nanocomposite, with rapid desalination and good recyclability. A plausible mechanism of salt adsorption and desorption is also presented. WMAC/MnF 2 O 4 exhibited significant application potential for the industrial desalination. Image 1 • WMAC and its MnFe 2 O 4 composite were developed as effective CDI electrode materials. • High specific capacitance of 425 F/g was obtained for WMAC/MnFe 2 O 4 nanocomposite. • High NaCl uptake capacity of 29.7 mg/g with rapid electrosorption rate & reusability. • WMAC/MnFe 2 O 4 nanocomposite is a promising candidate for desalination in industries. [ABSTRACT FROM AUTHOR]

Currently, there is a great environmental and economic need to convert polyethylene terephthalate bottles into high-value metal-organic framework materials. Metal-organic frameworks demonstrate great dominance over other materials owing to high surface area and exceptional porosities. Herein, a simple chemical approach was employed to produce metal-oxide nanoparticles (ZnO and Co 3 O 4) embedded mesoporous carbon (ZnO@MC and Co 3 O 4 @MC composites) via carbonization of polyethylene terephthalate bottles derived metal-organic frameworks for supercapacitor application. Very high specific surface areas of ∼2183 and ∼2503 m2g−1were achieved of ZnO@MC and Co 3 O 4 @MC composites for the first time. The mesoporous nature of ZnO@MC and Co 3 O 4 @MC composites was confirmed through BJH (32 Å and 42 Å) and DA (38 Å and 39 Å) pore size studies. The specific capacitances of ZnO@MC and Co 3 O 4 @MC composites were estimated to ∼97 and ∼180 F/g, respectively, at 5 mV/s using 6 M KOH in a two-electrode system from cyclic voltammetry analysis. The energy density of 68 Wh/kg at a power density of 149.1 W/kg was estimated for the Co 3 O 4 @MC composite. The galvanostatic charge discharge showed an excellent stability for Co 3 O 4 @MC composite (∼5.20% loss after 5000 segments). The Co 3 O 4 @MC composite demonstrated extraordinary supercapacitor performance because Co 3 O 4 having good Faradaic process and high theoretical capacitance. The symmetric supercapacitive performance of Co 3 O 4 @MC composite show good capacitance, stability and rate capability. Image 1 • Highly porous composites were fabricated using waste PET bottles. • The utilization of PET bottles takes a new route in solid waste management. • Electrochemical properties of composites were studied in two electrode system. • ZnO@MC and Co 3 O 4 @MC showed high specific surface area of ∼2183 and ∼2503 m2 g−1 • Supercapacitor electrodes with high specific energy & specific power were developed. [ABSTRACT FROM AUTHOR]