Utilizing flaxseed pulp waste as a valuable agricultural biomass product for the removal of Cu2+ and Ni2+

Abstract

In this study, the waste pulp obtained by removing mucilage in the structure of flaxseed was modified with acid to remove Cu²⁺ and Ni²⁺ metal ions, which have negative effects on human health and the environment. For adsorption studies, the effects of factors affecting adsorption (such as pH, initial metal concentration, adsorbent amount, contact time, temperature) on removal efficiency were investigated by classical univariate methods. In addition, kinetic models, thermodynamic studies, equilibrium isotherm models were investigated to define the adsorbent/adsorbate relationship. Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), brunauer–emmett–teller surface analysis (BET), surface zero charge point (pH_pzc) analyzes were examined for characterization. Based on the results, it was determined that the adsorption was compatible with the pseudo-first-order kinetic model for 298 and 308 K and the pseudo-second-order kinetic model for 318 and 328 K. In the adsorption fited the Langmuir isotherm, the maximum adsorption capacities for Cu²⁺ and Ni²⁺ were determined as 32.26 and 22.22 mg/g, respectively. In addition, the adsorption process was concluded that it was thermodynamically endothermic and spontaneous. It was determined that it was possible to utilize an agricultural waste that was obtained in large quantities and had not yet been utilized in this area.

Graphical Abstract