Performance of sesame straw cellulose, hemicellulose, and lignin biochars as adsorbents in removing benzo(a)pyrene from edible oil

Qiao-Li Yang,Xi-Chuang Cheng,Yu-Xiang Ma,Xue-De Wang,Zhao Qin,Hua-Min Liu

doi:10.1590/fst.49021

Abstract

The safety problems related to the occurrence of benzo(a)pyrene in edible oil have been a major threat to human health, and now significant attention has been to remove benzo(a)pyrene. So in this work, cellulose, hemicellulose, and lignin biochars were prepared, and then were used to remove benzo(a)pyrene from contaminated oil. Based on the nitrogen adsorption/desorption isotherms and the scanning election micrographs, the modified biochars had a huge specific surface area of 983.50-1915.55 m2/g and a well-developed porous structure. The modified biochars showed higher removal rate for benzo(a)pyrene than unmodified biochars. The highest adsorption (95.79%) of benzo(a)pyrene was achieved using the modified lignin biochar, which was therefore selected for evaluation of adsorptive capacity. The ability of the modified lignin biochar to adsorb benzo(a)pyrene was consistent with the pseudo-second order kinetic equation indicating mainly chemisorption, and it fit the Freundlich isotherm (R2 > 0.999), thereby revealing the occurrence of multilayer adsorption. The effect of π-π conjugation interaction and pore-filling together promoted the high adsorption performance of the modified lignin biochar. This work demonstrates that the modified lignin biochar could be a promising adsorbent for the removal of benzo(a)pyrene from edible oils.

Highlights

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) and a well-known carcinogen (Shi et al, 2017; Shin et al, 2016)
This study provides a promising adsorbent for the removal of benzo(a)pyrene from edible oils
The addition of ZnCl2 increased the yields of all biochars. This is because ZnCl2 favors depolymerization, dehydration, and redistribution of the biopolymers, and promotes the conversion of aliphatic to aromatic compounds; all of these transformations increase, the yield of biochar (Pezoti et al, 2014)

Summary

Introduction

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) and a well-known carcinogen (Shi et al, 2017; Shin et al, 2016). BaP has been shown to cause carcinogenic, teratogenic, mutagenic, and cytotoxic effects in various tissues and cell types (Moserová et al, 2009). BaP is present in a wide variety of food items, such as smoked foods (Rhee & Bratzler, 1970), edible oil (Camargo & Toledo, 2000), coffee, fried foods, and meat products (Wu et al, 2020). Edible oil can be heavily contaminated with BaP, because of their strong lipophilic property and wide distribution in the environment (Shi et al, 2017; Cotugno et al, 2021). How to remove BaP in edible oils effectively is a critical issue in the field of food safety

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Results

Conclusion