Nano‐zero valent iron impregnated cashew nut shell: a solution to heavy metal contaminated water/wastewater

Abstract

The present research is focused on the removal of Zn(II) ions from aqueous solution using nano zero-valent iron impregnated cashew nut shell (NZVI-CNS). The present system was investigated in batch mode operation. NZVI-CNS was prepared by the liquid-phase reduction process. The results showed that the NZVI-CNS exhibited superior adsorption capacity for the removal of Zn(II) ions. Adsorption isotherm and kinetic models were applied to explain the nature of the adsorption process. Adsorption kinetic data followed the pseudo-first order kinetic model. Moreover, the equilibrium adsorption data were best fitted with a Freundlich model. Langmuir monolayer adsorption capacity was calculated as 94.46 mg of Zn(II) ions/g of NZVI-CNS. The thermodynamic parameters explain that the present adsorption system was measured as feasible and spontaneous. This newly prepared adsorbent can be successfully applied for the different industrial wastewater treatment. Finally, the exploration asks about contemplated that NZVI-CNS has exhibited unrivalled adsorption limit. Additionally, NZVI-CNS is believed to be extremely green and monetarily neighbourly help for wastewater treatment. The results indicate that the feasible approach could be applied in agricultural waste biomass materials for the productive expulsion of heavy metals from aqueous solution and reusing agricultural wastes to facilitate their disposal problem.

Exploring the potential of cashew nutshells: A critical review of alternative applications

“…However, the use of commercial adsorbents such as polymers, minerals (e.g., zeolites), and other materials can be expensive and offer limited possibilities for regeneration and longer equilibrium times. Consequently, the research for abundant and cost-effective alternatives has gained popularity, leading to the study of biosorbents such as coconut shells, neem leaves, rice straw, corn cob, Pinus ash, chitosan, and CNS (Prabu et al 2016;Coelho et al 2018;Senthil Kumar et al 2018;Nuithitikul et al 2020;Geczo et al 2021;Wang 2021;Jain et al 2022;Kalaba et al 2022).…”

“…Adsorption studies were performed by varying the solution pH, adsorbent dose, initial concentration, contact time, and temperature. The maximum improvement observed is a 14-fold increase in adsorption capacity for Pb (II) (Senthil Kumar et al 2011bKumar et al , 2018Prabu et al 2016Prabu et al , 2021Coelho et al 2018;Nuithitikul et al 2020;Yahya et al 2020). These chemical treatments modify CNSc surface functional groups and eliminate impurities, creating more active sites for adsorption and potentially enhancing surface area and pore volume (Nuithitikul et al 2020).…”