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Novel Sm doped Cr 2 O 3 decorated MWCNTs nanocomposite photocatalyst was successfully prepared by a facile hydrothermal method for metoprolol (MET) degradation. A heterogeneous photo -Fenton like system was formed with the addition of H 2 O 2 for ultrasonic irradiation (US), visible light irradiation (Vis) and dual irradiation (US/Vis) systems. The intrinsic characteristics of Sm doped Cr 2 O 3 decorated MWCNTs nanocomposite was comprehensively performed using state-of-art characterization tools. Optical studies confirmed that Sm doping shifted the absorbance of Cr 2 O 3 towards the visible-light region, further enhanced by MWCNTs incorporation. In this study, degradation of metoprolol (MET) was investigated in the presence of Cr 2 O 3 nanoparticles, Sm doped Cr 2 O 3 and Sm doped Cr 2 O 3 decorated MWCNTs nanocomposites using sonocatalysis and photocatalysis and simultaneously. Several different experimental parameters, including irradiation time, H 2 O 2 concentration, catalyst amount, initial concentration, and pH value, were optimized. The remarkably enhanced sonophotocatalytic activity of Sm doped Cr 2 O 3 decorated MWCNTs could be attributed to the more formation of reactive radicals and the excellent electronical property of Sm doping and MWCNTs. The rate constant of degradation using sonophotocatalytic system was even higher than the sum of rates of individual systems due to its synergistic performance based on the kinetic data. A plausible mechanism for the degradation of MET over Sm-Cr 2 O 3 /MWCNTs is also demonstrated by using active species scavenger studies and EPR spectroscopy. Our findings imply that ( • OH), (h + ) and ( • O 2 - ) were the reactive species responsible for the degradation of MET based on the special three-way Fenton-like mechanism and the dissociation of H 2 O 2 . The durability and stability of the nanocomposite were also performed, and the obtained results revealed that the catalysts can endure the harsh sonophotocatalytic conditions even after fifth cycles. Mineralization experiments using the optimized parameters were evaluated as well. The kinetics and the reaction mechanism with the possible reasons for the synergistic effect were presented. Identification of degraded intermediates also investigated., (Copyright © 2021 Elsevier B.V. All rights reserved.) more...

Polysaccharide-based hydrogels offer a great overlook for environmental applications and help in the elimination of various noxious pollutants from the water system. Novel carrageenan and itaconic acid-based superadsorbent hydrogel having appreciable swelling properties and adsorption capacity towards Methylene blue (MB), Crystal violet (CV), and Methyl Red (MR) was synthesized by suspension polymerization technique. The swelling study showed the dependency upon the temperature in which the swelling rate increased with increasing temperature with a maximum swelling rate of 417% at 318 K. For ascertaining the maximum adsorption capacity, various influential parameters such as contact time, adsorbent dose, dye concentration, and temperature were systematically studied. Maximum adsorption capacity as calculated from the Langmuir isotherm was 2439.02, 1111.11, and 666.68 mg/g for MB, CV, and MR, respectively. Thermodynamic studies revealed the spontaneous nature of the undertaken dye adsorption experiment. Overall, the present study reveals that the synthesized superadsorbent hydrogel can be used as an efficient adsorbent for the removal of dyes from an aqueous solution., (Copyright © 2021 Elsevier B.V. All rights reserved.) more...

The construction of direct Z-scheme heterojunctions with high photocatalytic degradation ability is a theme of importance in both environmental and materials sciences, but still retains many unresolved challenges. In this article, we report the construction of Z-scheme CuInS 2 /Bi 2 MoO 6 heterostructure by in-situ hydrothermal reactions, demonstrating superior photocatalytic activity towards the degradation of tetracycline under visible light, compared to their individual components: that is to say 8 and 2.5 times those of CuInS 2 and Bi 2 MoO 6 , respectively. The photocatalytic performance of CuInS 2 /Bi 2 MoO 6 heterostructure is mainly ascribed to the effective charge transfer at the interface through the construction of a direct Z-scheme heterojunction, combined with a ternary sulfide semiconductor absorbing light in the useful region of the solar spectrum. This photocatalyst provides new insights on the fundamental aspects governing the mechanisms responsible for multicomponent photodegradation, while constituting already a promising candidate for practical environmental applications., (Copyright © 2021 Elsevier B.V. All rights reserved.) more...

Graphitic carbon nitride with suitably incorporated functionality has attracted much interest in the areas of environmental treatments, clean energy, sensing, and photocatalyst. However, the role of graphitic nanoporous carbon nitride (NCN) matrix from single carbon-nitrogen (C-N) source, aminoguanidine HCl as a precursor and close intimate contact between silver nanoparticles (Ag NPs) dispersed in NCN and bacteria has rarely been demonstrated. Herein, we demonstrate a nanostructure of Ag NPs-incorporated NCN sample (NCN@Ag) as an antibacterial agent against both wild type and the multidrug-resistant Escherichia coli (E. coli) pathogens. In-situ ultrasonication method was used to ensure the homogeneous mixing of the Ag NPs and a single C-N precursor at the molecular level so that pore size (PS) (9.17 nm) of SBA15 silica could be impregnated with ultrasonicated Ag NPs and a single C-N precursor. The porous structure, compositions, and structural information of the final nanocomposites were confirmed by using various analytical techniques such as XRD, TEM, BET surface area (SA) measurements, XPS, and UV. Then, the antibacterial activities of the NCN and NCN@Ag against both wild type and the multidrug-resistant Escherichia coli (E. coli) pathogens were also carried out and results from the in-vitro studies have shown the excellent bactericidal effect of the highly dispersed Ag NPs containing NCN@Ag sample against both E. coli strains. Results have confirmed that the antibacterial activity of the NCN@Ag sample is found to be higher than pure NCN, indicating that in-situ incorporated Ag NPs in NCN matrix have played significant role for enhancing antibacterial activities. Surprisingly, in the presence of NCN@Ag, the reduction in minimum inhibitory concentration (MIC) was higher (64-fold reduction) compared to its susceptible wild type (32-fold reduction) E. coli. These results indicate the potential application of NCN@Ag for inactivating infectious bacterial pathogens implicated in multidrug resistance., (Copyright © 2020 Elsevier B.V. All rights reserved.) more...

Biomass, the feedstock for biocrude and ultimately renewable diesel is a low energy density feedstock. The transport of this feedstock over long distance has been proven to be a major burden on the commercialisation of biorefining. Therefore, it has been generally accepted that biomass should be upgraded to biocrude (a relatively high energy density liquid) in close proximity to the biomass sources. The biocrude liquid would then be transported to a biorefinery. Biocrude contains large amounts of oxygen (generally up to 38 wt%) that is removed from the crude in the refining process. In this study, we have synthesised a range of spinel oxide based catalysts to remove oxygen from the biocrude during the catalytic fast pyrolysis. The activity of spinel oxide (MgB 2 O 4 where B = Fe, Al, Cr, Ga, La, Y, In) catalysts were screened for the pyrolysis reaction. While all the tested spinel oxides deoxygenated the pyrolysis vapour, MgCr 2 O 4 was found to be effective in terms of oxygen removal efficiency relative to the quantity of bio oil produced., (Copyright © 2020 Elsevier B.V. All rights reserved.) more...

In this study, we report a surface-enhanced Raman scattering (SERS)-active array film, which is based on regenerated cellulose hydrogels and gold nanorods (AuNRs), by combining a silicon rubber mask with a vacuum filtration method. This strategy enables the direct AuNR array formation on hydrogel surface with a precisely controlled number density. Moreover, the control of interparticle nanogap has been realized by the spatial deformation of hydrogels. A decrease in gaps between AuNRs deposited on hydrogels can result in SERS enhancement because 3D porous hydrogel structures turned into 2D closely packed hydrogel films during drying. In our experiments, SERS sensor arrays show excellent SERS activity to detect rhodamine 6 G and thiram down to 10 pM and 100 fM with competitive enhancement factors of 3.9 × 10 8 and 9.5 × 10 9 , respectively. Importantly, the resultant SERS-active arrays with nine sensor units can efficiently detect nine different analytes on a single substrates at a time. Moreover, we demonstrate that physical bending has little effect on the SERS activity of flexible AuNR array hydrogel films, which indicates the high reproducibility of SERS measurement. This SERS array film has great potential to simultaneously detect multiple hazards for the practical application of SERS analysis., (Copyright © 2020 Elsevier B.V. All rights reserved.) more...

Solid waste conversion to value-added products is a stepping stone towards sustainable environment. Herein, sesame oil cake (SOC), an oil industry waste was utilized as a precursor to develop hydrochar (HC) samples by varying reaction temperature (150-250 °C) and time span (2-8 h), chemically treated with 10% H 2 O 2 to optimize a sample with maximum yield and Pb(II) adsorption. Highest yield (29.2 %) and Pb(II) (24.57 mg/g at C o : 15 mg/L) adsorption was observed on SOCHC@200 °C/6 h, magnetized (mSOCHC@200 °C/6 h) for comparative study. XRD displayed highly crystalline SOCHC@200 °C/6 h and amorphous mSOCHC@200 °C/6 h, both having a characteristic cellulose peak at 14.9°. mSOCHC@200 °C/6 h displayed superparamagnetic behavior with 11.2 emu/g saturation magnetization. IR spectra confirmed the development of samples rich in oxygen containing functionalities; an additional peak for iron oxides appeared at 586 cm -1 in mSOCHC@200°C/6 h spectrum. Four major peaks at 531.9, 399.9, 348.2 and 284.7 eV, assigned to O 1s, N 1s, Ca 2p and C 1s, respectively were observed during XPS analyses. An additional peak at 710.3 eV, ascribed to Fe 2p was observed in mSOCHC@200C/6 h XPS spectrum, while a peak at 143.2 eV for Pb 4f appeared in spectra of both Pb(II) saturated samples. pH dependent (maximum at ∼6.7), exothermic Pb(II) adsorption was found. About 50-70% (at C o : 25 mg/L) adsorption on both SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h was accomplished in a minute, attaining equilibrium in 180 and 240 min, respectively. Error functions and superimposed q e, exp . and q e, cal. values supported Langmuir isotherm model applicability, with respective q m values of 304.9 and 361.7 mg/g at 25 °C for SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h. Kinetic data was fitted to PSO model. Highest (between 92.2 and 88.9 %) amount of Pb(II) from SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h was eluted by 0.01 M HCl., (Copyright © 2020 Elsevier B.V. All rights reserved.) more...

Herein, a novel nanocomposite (Fe 3 O 4 @TATS@ATA) was prepared and used for adsorptive removal of Pb(II) ions from aqueous environment. The magnetic nanocomposite (Fe 3 O 4 @TATS@ATA) was characterized using FTIR, TEM, SEM, EDX, element mapping analysis (EMA), TGA analysis, XRD patterns, VSM, BET analysis, XPS spectrum, and zeta potential. The FTIR study confirmed the modification of Fe 3 O 4 nanoparticles with triaminetriethoxysilane and 2-aminoterephthalic acid while XPS analysis (with peaks at 283.6, 285.1, 286.3, 284.5.0, 288.4 eV) displayed the presence of CSi, CN, OCNH, CC/CC and OCO functional groups, respectively on Fe 3 O 4 @TATS@ATA. The BET surface area, average pore size, pore volume and magnetization saturation for Fe 3 O 4 @TATS@ATA were found to be 114 m 2 /g, 6.4 nm, 0.054 cm -3 /g, and 22 emu/g, respectively. The adsorption isotherm data showed that Pb(II) adsorption onto Fe 3 O 4 @TATS@ATA fitted to Langmuir and Dubinin-Raduskevich isotherm model due to better R 2 value which was greater than 0.9 and q m of Pb(II) was 205.2 mg/g at pH 5.7 in 150 min. Adsorption kinetics data displayed that Pb(II) adsorption onto Fe 3 O 4 @TATS@ATA was fitted to the pseudo-second-order and Elovich kinetic models. Thermodynamic outcomes exhibited the exothermic and spontaneous nature of adsorption. Results showed that Fe 3 O 4 @TATS@ATA nanocomposite was promising material for efficient removal of toxic Pb(II) from aqueous environment., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest regarding the publication of this article, (Copyright © 2019 Elsevier B.V. All rights reserved.) more...

Modern-day practices are the major contributors in water quality deterioration, consequently results in clean water scarcity. Herein, co-precipitation procedure was adopted to develop a nanomagnetic copper ferrite/drumstick pod biomass (CuFe 2 O 4 /DC) composite, which was characterized, and optimized to sequester malachite green (MG) and lead (Pb(II)) in unary and binary systems from aqueous environment. Mesoporous CuFe 2 O 4 /DC surface with 16.96 m 2 /g BET surface area and acid functionalities predominance was observed. Under the studied experimental conditions, MG adsorption on CuFe 2 O 4 /DC in unary system was comparatively higher than that of Pb(II). MG and Pb(II) equilibrium results were fitted to Langmuir isotherm model, their respective maximum monolayer adsorption capacities at 328 K being 952.4 and 921.1 mg/g. On the other hand, binary system (in presence of MG) fastened Pb(II) adsorption kinetics and increased its uptake capacity. Additionally, humic acid (HA) matrix enhanced Pb(II) adsorption kinetics. Recovery studies showed maximal MG and Pb(II) elution with C 2 H 5 OH and 0.1 mol/L HCl, respectively. An 82.7% drop in Pb(II) adsorption was found after the first regeneration cycle, while only 17.6% fall in MG adsorption was witnessed after five consecutive regeneration cycles. Hence, it could be concluded that CuFe 2 O 4 /DC is a cost-effective and promising adsorbent for an efficient and rapid removal of Pb(II) and MG from both unary and binary systems., (Copyright © 2018 Elsevier B.V. All rights reserved.) more...

Mesoporous silicas carrying di-, tri-, or penta-amine functional groups were prepared by prior functionalization of a mesoporous silica with bromopropyl-functional groups followed by nucleophilic displacement of the bromine atoms by ethylenediamine, diethylenetriamine, or tetraethylenepentamine, respectively. A synthetic method was developed that gave a starting material with very high surface coverage by the 3-brompropyl groups. Batch tests were conducted to investigate the capabilities of the prepared adsorbents for the removal of copper, zinc, and cadmium from aqueous solutions. The metal adsorption capacities for these metals were determined as a function of the polyamine group used and the total nitrogen content. The tendency to chemisorb divalent metal ions was found to follow the order: Cu(2+)>Zn(2+)>Cd(2+). It was found that the ethylenediamine derivative unexpectedly exhibited the highest capacities. The metal sorption by the ethylenediamine functionalized silica was found to follow first order kinetics with rate constants for Cu(2+), Zn(2+) and Cd(2+) uptake of 0.028, 0.019, and 0.014 min(-1), respectively. The substituted mesoporous silicas showed high resistance to leaching of the grafted polyamine groups. Copper ions that were adsorbed at the surface of the mesoporous silicas can be recovered by washing with an aqueous solution of 1.0 M HNO(3). The activities of the recovered mesoporous silicas were between 80 and 90% of the original materials., (2010 Elsevier B.V. All rights reserved.) more...