Effects of Different Solvents on the Surface Acidic Oxygen-containing Functional Groups on Xanthoceras sorbifolia Shell

Abstract

This study reports the preparation of a novel biomaterial from a forestry residue-Xanthoceras sorbifolia shell (XSS)-by solvent modification. The effects of acid and base (hydrochloric acerbic, acetic acid, sodium hydroxide, ammonia water) and some organic solvents (ethanol, acetone, ethyl acetate, chloroform, petroleum ether, and n-hexane) on the surface acidic functional groups (SAFGs) on XSS were investigated. The amount of SAFGs was quantified using acid and alkali chemical titration methods, and the characteristics of virgin XSS were compared with treated ones by FT-IR spectroscopy. It was found that acid solutions can increase the concentration of SAFGs, while alkaline solutions reduce it. The XSS treated in 0.5 M HCl has the largest number of total acidic functional groups and phenolic hydroxyl groups. The shell extracted with 2 M acetic acid has the highest concentration of carboxyl. The SAFG contents were remarkably increased by treatments with ethanol and acetone, due to the outstanding enhancement of phenolic hydroxyl. These changes in the SAFGs of XSS brought about by treatments with various solutions could be a theoretical foundation for modifying this residue to create a new type of highly efficient absorbent material.

Malachite green adsorption by potassium salts‐activated carbons derived from textile sludge: Equilibrium, kinetics and thermodynamics studies

“…The phenolic group (weak) exhibited the most notable drop in density, followed by the carboxylic group (strong), while the lactonic group only displayed a slight decrease in density. Similar result was also reported by Liu et al, thus reaffirming that the alkali treatment significantly reduces the total acidic functional groups especially the phenolic hydroxyl group.…”

“…In other words, neutralization occurs when the surface acidic functional groups (carboxylic, lactonic and phenolic) are exposed to KOH (strong alkali). Potassium phenolate (salt) and water are produced from the neutralization of phenol hydroxyl (an organic weak acid) with KOH …”