The SARS-CoV-2 virus has spread globally and has severely impacted public health and the economy. Hand hygiene, social distancing, and the usage of personal protective equipment are considered the most vital tools in controlling the primary transmission of the virus. Converging evidence indicated the presence of SARS-CoV-2 in wastewater and its persistence over several days, which may create secondary transmission of the virus via waterborne and wastewater pathways. Although, researchers have started focusing on this mode of virus transmission, limited knowledge and societal unawareness of the transmission through wastewater may lead to significant increases in the number of positive cases. To emphasize the severe issue of virus transmission through wastewater and create societal awareness, we present a state of the art critical review on transmission of SARS-CoV-2 in wastewater and the potential remedial strategies to effectively control the viral spread and safeguard society. For low-income countries with high population densities, it is suggested to identify the virus in large scale municipal wastewater plants before following up with one-to-one testing for effective control of the secondary transmission. Ultrafiltration is an effective method for wastewater treatment and usually more than 4 logs of virus removal are achieved while safeguarding good protein permeability. Decentralized wastewater treatment facilities using solar-assisted disinfestation methods are most economical and can be effectively used in hospitals, isolation wards, and medical centers for reducing the risk of transmission from high local concentration sites, especially in tropical countries with abundant solar energy. Disinfection with chlorine, sodium hypochlorite, benzalkonium chloride, and peracetic acid have shown potential in terms of virucidal properties. Biological wastewater treatment using micro-algae will be highly effective in removal of virus and can be incorporated into membrane bio-reaction to achieve excellent virus removal rate. Though promising results have been shown by initial research for inactivation of SARS-CoV-2 in wastewater using physical, chemical and biological based treatment methods, there is a pressing need for extensive investigation of COVID-19 specific disinfectants with appropriate concentrations, their environmental implications, and regular monitoring of transmission. Effective wastewater treatment methods with high virus removal capacity and low treatment costs should be selected to control the virus spread and safeguard society from this deadly virus.
The paper evaluates the routes towards the evaluation of membranes using ZIF-62 metal organic framework (MOF) nano-hybrid dots for environmental remediation. Optimization of interaction of operating parameters over the rooted membrane is challenging issue. Subsequently, the interaction of operating parameters including temperature, pressure and CO2 gas concentration over the resultant rooted membranes are evaluated and optimized using response surface methodology for environmental remediation. In addition, the stability and effect of hydrocarbons on the performance of the resulting membrane during the gas mixture separation are evaluated at optimum conditions to meet the industrial requirements. The characterization results verified the fabrication of the ZIF-62 MOF rooted composite membrane. The permeation results demonstrated that the CO2 permeability and CO2/CH4 selectivity of the composite membrane was increased from 15.8 to 84.8 Barrer and 12.2 to 35.3 upon integration of ZIF-62 nano-glass into cellulose acetate (CA) polymer. Subsequently, the optimum conditions have been found at a temperature of 30 °C, the pressure of 12.6 bar and CO2 feed concentration of 53.3 vol%. These optimum conditions revealed the highest CO2 permeability, CH4 permeability and CO2/CH4 separation factor of 47.9 Barrer, 0.2 Barrer and 26.8. The presence of hydrocarbons in gas mixture dropped the CO2 permeability of 56.5% and separation factor of 46.4% during 206 h of testing. The separation performance of the composite membrane remained stable without the presence of hydrocarbons for 206 h.
Carbon nanotubes (CNTs), are safe, biocompatible, bioactive, and biodegradable materials, and have sparked a lot of attention due to their unique characteristics in a variety of applications, including medical and dye industries, paper manufacturing and water purification. CNTs also have a strong film-forming potential, permitting them to be widely employed in constructing sensors and biosensors. This review concentrates on the application of CNT-based nanocomposites in the production of electrochemical sensors and biosensors. It emphasizes the synthesis and optimization of CNT-based sensors for a range of applications and outlines the benefits of using CNTs for biomolecule immobilization. In addition, the use of molecularly imprinted polymer (MIP)-CNTs in the production of electrochemical sensors is also discussed. The challenges faced by the current CNTs-based sensors, along with some the future perspectives and their future opportunities, are also briefly explained in this paper.
This study deals with the preparation of activated carbon (CDSP) from date seed powder (DSP) by chemical activation to eliminate polyaromatic hydrocarbon-PAHs (naphthalene-C10H8) from synthetic wastewater. The chemical activation process was carried out using a weak Lewis acid of zinc acetate dihydrate salt (Zn(CH3CO2)2·2H2O). The equilibrium isotherm and kinetics analysis was carried out using DSP and CDSP samples, and their performances were compared for the removal of a volatile organic compound-naphthalene (C10H8)-from synthetic aqueous effluents or wastewater. The equilibrium isotherm data was analyzed using the linear regression model of the Langmuir, Freundlich and Temkin equations. The R2 values for the Langmuir isotherm were 0.93 and 0.99 for naphthalene (C10H8) adsorption using DSP and CDSP, respectively. CDSP showed a higher equilibrium sorption capacity (qe) of 379.64 µg/g. DSP had an equilibrium sorption capacity of 369.06 µg/g for C10H8. The rate of reaction was estimated for C10H8 adsorption using a pseudo-first order, pseudo-second order and Elovich kinetic equation. The reaction mechanism for both the sorbents (CDSP and DSP) was studied using the intraparticle diffusion model. The equilibrium data was well-fitted with the pseudo-second order kinetics model showing the chemisorption nature of the equilibrium system. CDSP showed a higher sorption performance than DSP due to its higher BET surface area and carbon content. Physiochemical characterizations of the DSP and CDSP samples were carried out using the BET surface area analysis, Fourier-scanning microscopic analysis (FSEM), energy-dispersive X-ray (EDX) analysis and Fourier-transform spectroscopic analysis (FTIR). A thermogravimetric and ultimate analysis was also carried out to determine the carbon content in both the sorbents (DSP and CDSP) here. This study confirms the potential of DSP and CDSP to remove C10H8 from lab-scale synthetic wastewater.