Heteroatom doped biochar-aluminosilicate composite as a green alternative for the removal of hazardous dyes: Functional characterization and modeling studies.

In this work, a novel nitrogen-doped biochar bentonite composite was synthesized by a single-pot co-pyrolysis method. Batch studies were conducted to evaluate the performance of the developed composite in eliminating synthetic dyes from the aqueous matrix. Energy dispersive X-ray spectroscopy analysis and field emission scanning electron microscopy imaging confirmed the N doping and bentonite impregnation into biochar. X-ray photoelectron spectroscopy analysis revealed that the N atoms were doped interstitially into the carbon matrix of biochar in the form of pyridinic and pyrrolic nitrogen. Simultaneous heteroatom doping and bentonite impregnation reduced the specific surface area to 41.721 m2 g-1 but improved the adsorption capacity of biochar for dye adsorption. Further experimental studies depicted that simultaneous bentonite impregnation and N doping into the biochar matrix is beneficial for direct blue-6 (DB-6) and methylene blue (MB) removal and maximum adsorption capacities of 53.17 mg. g-1 and 41.33 mg. g-1 were obtained for MB and DB-6, respectively, at varying conditions. Adsorption energetics of the dyes with the developed composite portrayed the spontaneity of the process through negative ΔG values. The Langmuir and Freundlich isotherm models fitted the best for MB and DB-6 adsorption. The monolayer adsorption capacity and favourability factor for MB and DB-6 adsorption were calculated to be 54.15 mg. g-1 and 0.217, respectively from the best-fitted isotherms. Based on density functional theory calculations and spectroscopic studies, major interactions governing the adsorption were predicted to be charge-based interactions, π-π interactions, H-bonding, and Lewis acid-base interactions.

Performance analysis of hydrochar derived from catalytic hydrothermal carbonization in the multicomponent emerging contaminant systems: Selectivity and modeling studies.

In this work, as an alternative to pyrochar, catalytic hydrothermal carbonization has been employed to synthesize hydrochar to eliminate emerging contaminants in multicomponent systems. The hydrochar has been synthesized using a single step catalytic hydrothermal carbonization at low temperature (200 °C) without any secondary activation with high specific surface area and very good adsorption efficiency for the removal of emerging contaminants. The synthesized hydrochar (HC200) was characterized using various analytical techniques and found to have porous structure with 114.84 m2.g-1 of specific surface area and also contained various oxygen-containing functionalities. The maximum adsorption efficiencies of 92.4 %, 85.4 %, and 82 % were obtained for ibuprofen, sulfamethoxazole, and bisphenol A, respectively. Humic acid, a naturally occurring organic compound had a negligible effect on the adsorption of the selected contaminants. The hydrochar's selectivity towards the emerging contaminants in binary and ternary multicomponent systems was in the order of ibuprofen > sulfamethoxazole > bisphenol A.

UiO-66 octahedrons for adsorptive removal of direct blue-6: process optimization, interaction mechanism, and phytotoxicity assessment.

The materials for water treatment have been evolving in multitude of dimensions, indicating the importance of water reuse and increasing level of water pollution around the globe. Among the various materials that are utilized in wastewater treatment, the material that has attracted the research community for the past decades is the metal organic framework (MOF). In this work one of the water stable and microporous MOF, UiO-66, and its aminated version has been employed to adsorb an anionic azo dye, direct blue-6 (DB-6), from the aqueous matrix. Performance of both the MOFs was compared to know the efficiency under varying solution conditions. The optimized parameters for DB-6 adsorption by UiO-66 was performed using response surface methodology. This numerical optimization was further extended with canonical and ridge analysis. Under optimal conditions, the materials were exhibiting a good adsorption capacity of 754.4 mg/g. The materials were analyzed in terms of morphology, crystallinity, thermal stability, and surface area using instruments like X-ray diffraction, electron microscopy, thermogravimetric analysis, and BET surface area analysis. The mechanism of interaction between UiO-66 and DB-6 molecule was elucidated with the help of XPS analysis which helps to know the main interacting group of UiO-66. This study was concluded with a phytotoxicity analysis of DB-6 and the antioxidant system of Vigna radiata assessed using pre and post adsorbed water.

Valorization of sawdust by mineral acid assisted hydrothermal carbonization for the adsorptive removal of bisphenol A: A greener approach.

sawdust was valorized using acid-assisted hydrothermal carbonization and used in the removal of endocrine disruptor bisphenol A (BPA). The effect of acid addition on the hydrothermal carbonization of sawdust and removal of BPA was studied. Two different hydrochars were prepared using deionized water (HCD) and hydrochloric acid solution (HCAH) as feed water. The prepared hydrochars were characterized using FESEM, EDS, XRD, Raman spectroscopy, FTIR, TGA, and surface area analysis to study the structural and functional changes. Then they were compared in the removal of bisphenol A. Out of the two hydrochars prepared, acid-assisted hydrothermal carbonized hydrochar (HCAH) showed better removal efficiency. Hence, HCAH was used to study the influence of different parameters like pH, adsorbent dosage, and initial bisphenol A concentration by one variable at a time approach. Further, the study of interactive effects and optimization of adsorption of bisphenol A onto HCAH was carried out using RSM-CCD. The isotherm, kinetics, and thermodynamic studies revealed that the adsorption of bisphenol A could be explained by the Freundlich isotherm, pseudo-second-order kinetics fitted well in all the initial BPA concentrations, and the adsorption of bisphenol A onto HCAH was exothermic and spontaneous.

Electrocatalytic removal of fluroquinolones from simulated pharmaceutical effluent: Chemometric analysis, chemical blueprint of electrodes and generated sludge.

Electrocatalytic removal of fluroquinolones from simulated pharmaceutical effluent is studied in this work. The effects of parameters like NaCl concentration, pH and initial concentration of Ofloxacin were studied. The synergistic effect of H2O2 on the degradation of Ofloxacin paves the way to move towards radical based chemistry. The process was modelled and statistically evaluated through Central Composite Design approach towards the maximum concentration of Ofloxacin degraded (for 0.8 mM) as 0.46 mM at pH-3.0 and the concentration of H2O2 at 0.2 mM. The model was analyzed mathematically and observed as saddle response based on canonical and ridge analysis. The process follows pseudo first order kinetics with k = 0.047 min-1 and reaction rate of 13.6 mg.L-1.min-1. The mineralization efficiency of the process was studied using Total Organic Carbon analysis and 76.5% removal efficiency was obtained on the simulated pharmaceutical effluent containing Ofloxacin, Ciprofloxacin and Norfloxacin. The crystal structure of the green and red colour sludge was determined by XRD to be lepidocrocite (a = 3.87 Å, b = 12.4 Å, c = 3.06 Å) and gupeiite (a = 5.6620 Å), respectively. The elemental composition of sludge and electrodes were found using SEM-EDX. Morphological change in electrode surface was determined using roughness plot.

Can human overcome viral hijack-? Comprehensive review on COVID-19 in the view of diagnosis and mitigation across countries.

The novel COVID-19, a pandemic disease, is showing an alarming spread and severity throughout the world. Globally, the community transmission of this disease is affecting people in large clusters and so it is necessary to mitigate and control them in order to minimise the social and economic consequences. This review emphasize on the origin of the coronoviral epidemics, discussion on the structural and functional basis of SARS-CoV-2, epidemiology, pathognomonic symptoms, fatality, available rapid diagnostic methods and proposed possible treatment methods for the treatment of COVID-19. The diagnostic markers with respect to genetic material of the virus based on PCR, CRISPR & APTAMER and with respect to proteins based on Antigens were discussed which provides new arena for the development. In control of a pandemic situation the policy adoption and implementation by the governments plays a major role and the policy implementation in different countries are discussed which establishes the effectiveness of the policies framed by the governments. The effectiveness of ethnic traditional medicines of various countries such as India and China in Immunity enhancement, along with their utilisation is also discussed. This review provides an insights towards the COVID-19 which helps in continuous investigation on different dimensions which could help us to understand the mysteries behind the havoc created by this invisible creature.