SOFT MODIFICATION AND FUNCTIONALIZATION OF LIGNOCELLULOSIC BIOMASS USED AS A LOW-COST EFFICIENT BIOSORBENT TO REMOVE BASIC FUCHSINE FROM AQUEOUS SOLUTION

Abstract

This study proposes a new modification of lignocellulosic biomass based on apricot kernel shells with composite activation KI/KOH and functionalized with a tolerant material (MgO) powder. Apricot kernel shells (NAK), modified apricot kernel shells (MAK) and doped apricot kernel shells (DAK) obtained were characterized using various methods, such as infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and point of zero charge (pHpzc). The adsorbents were also evaluated in batch adsorption, using basic fuchsine dye (BF) to determine the performance and specific capacity of the adsorption process. The results showed that only 90 min and 0.1 g of DAK or MAK are sufficient to remove 93% and 91%, respectively, of basic fuchsine from aqueous solutions with a concentration of 20 mg/L in a volume of 100 mL. The MAK and DAK adsorbents can be reused for 5 cycles before their yield decreases below 50%, without requiring complex regeneration procedures, only drying for 4 h at 105°C. The evolution of adsorption was analyzed under different parameters, such as contact time, initial dose of adsorbent, initial dye concentration, initial pH, and temperature. The kinetic adsorption models indicate that the pseudo-second-order model was more suitable than the pseudo-first-order and intraparticle diffusion models for describing the adsorption process. The equilibrium adsorption data of BF were better fitted by the Langmuir isotherm, compared to the Freundlich and Temkin isotherms.