Sustainable Chromium Recovery From Wastewater Using Mango and Jackfruit Seed Kernel Bio-Adsorbents.

Deen Dayal Giri,Abeer Hashem,Maulin Shah,Elsayed Fathi Abd_Allah,Dan Bahadur Pal,Neha Srivastava

doi:10.3389/fmicb.2021.717848

Abstract

Wastewater is a rich source of valuable chemicals of industrial importance. However, their economic recovery is crucial for sustainability. The objective of the present work is to recover hexavalent chromium (Cr VI) as a value-added transition metal from wastewater cost-effectively; the biosorbent derived from seed kernels of mango (M) and jackfruit (JF) were applied for removing the metal from simulated wastewater. The functional groups of the biomass were analysed with the help of Fourier transform infrared (FTIR) spectroscopy, micrographs were generated using a scanning electron microscope, and crystallinity was determined by an x-ray diffractometer (XRD). The concentration of Cr VI in wastewater was analysed by an inductively coupled plasma optical emission spectrometer (ICP-OES). Process parameters (pH, dose, contact time, temperature, and initial concentration) were optimized for efficient Cr VI adsorption using a response surface methodology-based Box–Behnken design (BBD) employing Design-software 6.0.8. The batch experiment at room temperature at pH 4.8 and Cr VI removal ∼94% (M) and ∼92% (JF) was achieved by using a 60-mg dose and an initial Cr (VI) concentration of 2 ppm in 120 min. The equilibrium Cr binding on the biosorbent was well explained using Freundlich isotherm (R2 = 0.97), which indicated the indirect interactions between Cr (VI) and the biosorbent. Biosorption of Cr (VI) followed the pseudo-order and intra-particle diffusion models. The maximum adsorption capacity of the M and JF bio-adsorbent is 517.24 and 207.6 g/mg, respectively. These efficient, cost-effective, and eco-friendly biosorbents could be potentially applied for removing toxic Cr (VI) from polluted water.

Highlights

In the recent past, rapid industrialization and over-exploitation of resources have drastically polluted our natural water bodies with many toxic heavy metals
The presence of heavy metals severely degraded the quality of the aquatic habitat
The harmful effect of heavy metal varies from metal to metal; their trace concentration in parts per million or parts per billion could be much harmful in chronic exposure to humans and animals (Bharath et al, 2020)

Summary

Introduction

Rapid industrialization and over-exploitation of resources have drastically polluted our natural water bodies with many toxic heavy metals. The presence of heavy metals severely degraded the quality of the aquatic habitat. The harmful effect of heavy metal varies from metal to metal; their trace concentration in parts per million (ppm) or parts per billion (ppb) could be much harmful in chronic exposure to humans and animals (Bharath et al, 2020). After entry into the environment, the non-biodegradable toxic heavy metals persist and enter the food chain and adversely affect different living organisms. It is necessary to restrict the discharge of heavy metals in the aquatic ecosystem and remediation of polluted waterbody to ensure good health for animals including humans

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