The preparation of low-cost adsorbent for heavy metal based on furfural residue

ABSTRACT

In this research, with furfural residue as the raw material and phenolic resin as the adhesive, low-cost adsorbent based on furfural residue was made, and characterized with scanning electron microscopy (SEM), nitrogen adsorption–desorption analysis, and Fourier transform infrared spectrophotometry (FTIR). The adsorbent was used to adsorb Cd²⁺, Ni²⁺, Pb²⁺, Cu²⁺ and Zn²⁺ in the water, and the experimental conditions of adsorption and elution were researched. In addition, the thermodynamics and dynamics mechanism of the adsorption were also investigated. The results demonstrate the lignin, cellulose and hemicellulose in furfural residue were bonded and solidified, and a new adsorbent based on furfural residue was obtained. In the medium of pH 5–7, the resin presented powerful adsorbing capacity toward heavy metal in water, and the adsorption capacities of the material for Cd²⁺, Pb²⁺, Zn²⁺, Cu²⁺ and Ni²⁺ were found to be 18.3, 98.2, 34.8, 45.1 and 14.7 mg/g, respectively. The adsorptive behavior was proved to be consistent with the Freundlich adsorption isotherm model and the second-order rate equation. The adsorption was driven by entropy, and it was an endothermic and spontaneously physical process. After the application of adsorbent, 1 mol/L nitric acid could be used for regeneration. The adsorbent has been applied to the treatment of wastewater and the results are satisfactory.

KEYWORDS:

• Adsorbent
• furfural residue
• heavy metal
• lignin phenolic resin
• processes
• synthesis
• waste utilization
• wastewater