Two notable porous polynuclear materials ER1.30@CMERI-2020 and ER1.65@CMERI-2020 for remedial solution of fluoride, PWEs and anionic dyes from contaminated water bodies: fabrication of household water purification unit

ABSTRACT ERcrude@CMERI-2020, a transition metal enriched polynuclear porous earthy regolith (ER), was crushed, sieved and subsequently chemically ammended by aqueous 0.3(M) SiO2 solution, to synthesize two novel geo-chemical-composites with specific silica-sesquioxide (S-S) ratio: ER1.30@CMERI-2020 and ER1.65@CMERI-2020. ER1.30@CMERI-2020 (BET surface area 96.39 m2/g) exhibited excellent fluoride adsorption capacity (70.6 mg/g) via ion exchange mechanistic pathway; following Pseudo second-order kinetics and Freundlich isotherm model. Results from real fluoride contaminated groundwater trials, effects of interfering anions and resusability up to five times established the on-field viability of ER1.30@CMERI-2020. Furthermore, ER1.65@CMERI-2020 revealed a promising prospect towards purification of Paper Workhouse Effluents (PWEs), by reducing several water-quality controlling parameters. UV-vis adsorption kinetics and decrease in surface area (43.91 m2/g to 24.59 m2/g) of ER1.65@CMERI-2020 after PWEs sorption confirmed the experimental findings. Zeta potential analysis and HR-TEM showed the deposition of PWEs on specific favourable sites of ER1.65@CMERI-2020. Additionally, ER1.65@CMERI-2020 exhibited potential efficacy towards sorption of specific anionic dyes (Congo Red, Methyl Blue, Alizarin S, Bromothymol Blue). Based on the experimental findings, a simple domestic level gravity-fed water purification unit was developed, comprising of a four (04) stage filtration cartridge, utilizing ER1.30@CMERI-2020 and ER1.65@CMERI-2020 alongwith certain amounts of conventional adsorbents (silex and activated charcoal) in a specific ratio.The investigational discoveries as well as fabrication of the unique houlsehold prototype is hitherto unexplored, unique of its kind; making the work unprecedented.