Fabrication of novel glutathione-Fe3O4-loaded/activated carbon encapsulated sand bionanocomposites for enhanced removal of Diethyl phthalate from aqueous environment in a vertical flow reactor.

The extensive use of plasticizers in various industries has made Diethyl phthalate (DEP), a serious threat to the environment and ecological water security, owing to its complex-structure and low-biodegradability. Thus, the present study aimed to design a sustainable sand-coated nano glutathione (GSH) -Fe3O4-loaded/activated carbon (AC) bionanocomposite (AC-GSH-Fe3O4@sand bionanocomposite) for effective removal of DEP from water. Characterization results suggested bionanocomposites' rough and irregular texture due to the uneven distribution of AC and Fe3O4 nanoparticles over the sand. The XRD spectra indicated high crystallinity of bionanocomposites, while the FTIR spectra confirmed the presence of all individual components, i.e., GSH, AC, Fe3O4, and sand. EDX-mapping, AFM, and TGA further verified its elemental composition, topographical changes and thermal stability. The influence of pH (3, 7, 9), bed height (2, 4, 6) cm, and flow rate (2.5, 3.5, 4.5) mL min-1 were studied in a dynamic system with an initial DEP concentration of 50 mg L-1 to investigate the removal behavior of the bionanocomposites. The best DEP removal efficiency (90.18 %) was achieved over 28-hours at pH 9, bed-height-4 cm, and flow-rate-3.5 mL min-1, with an optimum qmax-200.25 mg g-1 as determined through Thomas-model. Breakthrough curves were predicted using various column models, and the corresponding parameters essential for column-reactor process design were calculated. The high reusability up to the 10th cycle (≥ 83.32%) and the effective treatment in complex matrices (tap-water: 90.11 %, river-water: 89.72 %, wastewater: 83.83%) demonstrated bionanocomposites' prominent sustainability. Additionally, the production cost at 6.64 USD per Kg, underscores its potentiality for industrial application. Phytotoxicity assessment on mung-bean revealed better root (5.02 ± 0.27) cm and shoot (17.64 ± 0.35) cm growth in the bionanocomposite-treated DEP samples over the untreated samples. Thus, AC-GSH-Fe3O4@sand bionanocomposites could be considered a highly-sustainable, low-cost technique for the effective removal of DEP and other phthalate-esters from contaminated matrices.

Chitosan anchored nZVI bionanocomposites for treatment of textile wastewater: Optimization, mechanism, and phytotoxic assessment.

In recent years, there has been a growing focus on treating textile wastewater due to its escalating threat to aquatic ecosystems and exposed communities. The present study investigates the adsorption efficacy of biopolymer functionalized nanoscale zero-valent iron (CS@nZVI) composite for the treatment of textile wastewater using the RSM-CCD model. The structure and morphology of CS@nZVI were characterized using XRD, FTIR, FESEM, and EDX. CS@nZVI was then evaluated for its adsorption potential in removing COD, color, and other physico-chemical parameters from textile wastewater. The results showed the high efficacy of CS@nZVI for COD and color removal from textile wastewater. Under optimal conditions (pH 6, contact time 60 min, and 1.84 g CS@nZVI), COD removal reached a maximum of 85.53%, and decolorization efficiency was found to be 89.73%. The coefficient of determination R2 (0.98) and AIC (269.75) values suggested quadratic model as the best-fitted model for optimizing the process parameters for COD removal. Additionally, the physico-chemical parameters were found to be within permissible limits after treatment with CS@nZVI. The influence of coexisting ions on COD removal followed the order PO43- > SO42- > Cl- >Na+ > Ca2+. The kinetics data fitted well with the pseudo-first-order reaction, indicating physisorption as the primary mechanism. The thermodynamic study revealed the endothermic nature of the removal process. Reusability tests demonstrated that great regeneration capacity of spent CS@nZVIafter five consecutive cycles. Furthermore, toxicological studies showed reduced toxicity in treated samples, leading to improved growth of Vigna radiata L. These findings suggest that CS@nZVI bionanocomposites could serve as an efficient, cost-effective, and eco-friendly remediation agent for the treatment of textile effluents, presenting significant prospects for commercial applications.

Facile synthesis of biopolymer decorated magnetic coreshells for enhanced removal of xenobiotic azo dyes through experimental modelling.

Since contamination of xenobiotics in water bodies has become a global issue, their removal is gaining ample attention lately. In the present study, nZVI was synthesized using chitosan for removal of two such xenobitic dyes, Bromocresol green and (BCG) and Brilliant blue (BB), which have high prevalence in freshwater and wastewater matrices. nZVI functionalization prevents nanoparticle aggregation and oxidation, enhancing the removal of BCG and BB with an efficiency of 84.96% and 86.21%, respectively. XRD, FESEM, EDS, and FTIR have been employed to investigate the morphology, elemental composition, and functional groups of chitosan-modified nanoscale-zerovalent iron (CS@nZVI). RSM-CCD model was utilized to assess the combined effect of five independent variables and determine the best condition for maximum dye removal. The interactions between adsorbent dose (2-4 mg), pH (4-8), time (20-40 min), temperature (35-65 0C), and initial dye concentration (40-60 mg/L) was modeled to study the response, i.e., dye removal percentage. The reaction fitted well with Langmuir isotherm and pseudo-first-order kinetics, with a maximum qe value of 426.97 and 452.4 mg/g for BCG and BB, respectively. Thermodynamic analysis revealed the adsorption was spontaneous, and endothermic in nature. Moreover, CS@nZVI could be used up to five cycles of dye removal with remarkable potential for real water samples.

Fabrication of glutathione functionalized self-assembled magnetite nanochains for effective removal of crystal violet and phenol red dye from aqueous matrix.

A novel fabrication of magnetite (Fe3O4) nanochains, surface functionalized with glutathione (GSH), has been attempted through a basic wet reduction method, coalesced with oxidative etching for the removal of crystal violet (CV) and phenol red (PR) from an aqueous solution. The structural and functional characterizations of GSH@Fe3O4 MNPs were performed using SEM-EDX, DLS, XRD, and FTIR. The nanochain-structured adsorbent was found to have an average size of 24 ± 1.29 nm and a zeta potential value of - 6.44 mV. The batch experiments showed that GSH@Fe3O4 MNPs have a brilliant removal efficiency of 97% and 79% for CV and PR dyes, respectively, within a period of 60 min. The influence of different operational parameters like adsorbent dosage, pH, temperature, reaction time, and initial dye concentration on the removal behaviour of the adsorbent was studied in detail. The adsorbate-adsorbent reaction was tested over isotherm models, and the reaction fitted well for Langmuir isotherm with an excellent qmax value of 1619.5 mg/g and 1316.16 mg/g for CV and PR dye, respectively. The experimental results were also validated using different reaction kinetics, and it was found that the pseudo-first-order model fits well for PR dye adsorption (R2 = 0.91), while adsorption of CV dye was in best agreement with the pseudo-second-order kinetic model (R2 = 0.98). Thermodynamic studies revealed that the adsorption reaction was spontaneous and endothermic in nature. Furthermore, GSH@Fe3O4 MNPs can be reused effectively up to 5 cycles of dye removal. Major mechanisms involved in the adsorption reaction were expected to be electrostatic attraction, hydrogen bonding, and π-interactions. The efficiency of GSH@Fe3O4 MNPs in real water samples suggested that it has a high potential for dye removal from complex aqueous systems and could be used as an effective alternative for remediation of dyes contaminated water.

Nanotechnology-Based Strategies for the Management of COVID-19: Recent Developments and Challenges.

COVID-19 is a respiratory disease caused by a newly identified coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since its inception in late December 2019, COVID-19 has led to a tremendous loss of human life worldwide. To overcome the unprecedented challenges posed by the COVID-19 pandemic to the public and economic health, strengthening the healthcare system is of utmost need. In this regard, research communities are putting efforts into developing an advanced healthcare system that could reduce the severe impacts of this pandemic. Nanotechnology is an advanced technology that has contributed significantly to produce powerful arsenals for the frontline warriors in this battle against COVID-19. It has offered opportunities for the development of fast and accurate point-of-care testing, efficient therapeutics and vaccines, potent sanitizers, facemasks, and personal protective equipment against SARS-CoV-2. However, associated toxicity, lengthy procedures of clinical trials, and uncertain health risks are some points that are still debatable. The present paper provides an overview of COVID-19 specific therapeutics and vaccines with an emphasis on nano-based strategies, which are significantly contributing towards the success of mitigation measures and strategies against COVID-19. Furthermore, the associated challenges, current limitations, and opportunities in this field are discussed.

Current understanding of the influence of environmental factors on SARS-CoV-2 transmission, persistence, and infectivity.

Coronavirus disease 2019 (COVID-19) has emerged as a significant public health emergency in recent times. It is a respiratory illness caused by the novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was initially reported in late December 2019. In a span of 6 months, this pandemic spread across the globe leading to high morbidity and mortality rates. Soon after the identification of the causative virus, questions concerning the impact of environmental factors on the dissemination and transmission of the virus, its persistence in environmental matrices, and infectivity potential begin to emerge. As the environmental factors could have far-reaching consequences on infection dissemination and severity, it is essential to understand the linkage between these factors and the COVID-19 outbreak. In order to improve our current understanding over this topic, the present article summarizes topical and substantial observations made regarding the influences of abiotic environmental factors such as climate, temperature, humidity, wind speed, air, and water quality, solid surfaces/interfaces, frozen food, and biotic factors like age, sex, gender, blood type, population density, behavioural characteristics, etc. on the transmission, persistence, and infectivity of this newly recognized SARS-CoV-2 virus. Further, the potential pathways of virus transmission that could pose risk to population health have been discussed, and the critical areas have been identified which merits urgent research for the assessment and management of the COVID-19 outbreak. Where possible, the knowledge gaps requiring further investigation have been highlighted.