Thermally activated adsorbent over chemically modified Carica papaya tree adsorbents for removal of chromium from tannery wastewater

Authors: HASHEM, MD - Khulna University Of Engineering & Technology (KUET); MIM, SADIA - Khulna University Of Engineering & Technology (KUET); PAYEL, SOFIA - Khulna University Of Engineering & Technology (KUET); JABEEN, HUSNE - Khulna University Of Engineering & Technology (KUET); SAKIB, MD - Khulna University Of Engineering & Technology (KUET); MIZAN, AL - Khulna University Of Engineering & Technology (KUET); BASARAN, BAHRI - Ege University; YAPICI, ALI - Canakkale University; Sarker, Majher

Submitted to: Bioresource Technology Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2023
Publication Date: 11/11/2023
Citation: Hashem, M.A., Mim, S., Payel, S., Jabeen, H., Sakib, M., Mizan, A., Basaran, B., Yapici, A., Sarker, M.I. 2023. Thermally activated adsorbent over chemically modified Carica papaya tree adsorbents for removal of chromium from tannery wastewater. Bioresource Technology Reports. 25. Article 101692. https://doi.org/10.1016/j.biteb.2023.101692.
DOI: https://doi.org/10.1016/j.biteb.2023.101692

Interpretive Summary: In this research study, bio adsorbent has been developed from the residue of papaya tree as an abundant biomass. The bio-adsorbent have been produced by chemical modification and thermal activation of the biomass. The developed bio-adsorbents have been characterized and their application potentiality have been evaluated based on their efficacy in removing the toxic metal such as chromium from the tannery wastewater. It is found that thermally activated adsorbent shows better performance than the chemically modified adsorbent by removing 99.88% of chromium from the tannery wastewater at optimum condition. Hence, this research demonstrates that agricultural waste can be utilized to reduce the pollution load of the environment.

Technical Abstract: This work investigated the convenience of thermally prepared adsorbent over chemically modified absorbent made from Carica papaya tree for chromium eradication from tannery wastewater. Chemically modified Carica papaya tree adsorbents were developed employing zinc chloride (ZnCl2), potassium hydroxide (KOH), and nitric acid (HNO3) individually followed by calcination at 600°C where, thermally modified adsorbents were prepared by direct calcination at 600°C for 3 h. The potentiality of differently prepared adsorbents was evaluated by considering their efficacy in removing chromium from wastewater as well as the process simplicity. The chromium removal efficiencies obtained for ZnCl2, KOH, HNO3 modified and thermally modified Carica papaya tree adsorbents were 71.33%, 73.58%, 76.25%, and 99.89%, respectively. The chromium adsorption on different Carica papaya tree adsorbents was assessed by Fourier Transform Infrared (FT-IR) spectroscopy and Energy-dispersive X-ray spectrometry (EDX) analysis. The optimum condition for the maximum adsorbent’s efficacy was determined by conducting the batch experiments with varying the adsorbent doses, stirring time and settling time. Results revealed the maximum chromium removal efficiency of thermally modified Carica papaya tree adsorbent was 99.88% at 0.25 g/25 mL of adsorbent dose for a 20 min stirring time. Analysis from Freundlich and Temkin isotherm revealed the adsorption reaction as an endothermic chemisorption reaction with strong interaction between the adsorbent and chromium ion. In terms of kinetics, the Pseudo 2nd order equation had the best fitting with the experimental data considering the regression coefficient value (R2=0.9997). Thermally modified adsorbent from agricultural waste such as Carica papaya tree can be used to reduce pollution load from tannery wastewater.