Preparation Of Sulfonated Humic Acid Resin And Its Selective Adsorption Of Pb²⁺ From Lead Containing Wastewater

In recent years,with the rapid development of battery production and metal smelting industry,a large amount of lead containing wastewater is discharged.The increasing water pollution poses a great threat to the environment and human life.In this paper,lignite humic acid was used as raw material to modify its functional groups and cross-linked to prepare adsorption resin.The preparation of adsorbent,adsorption performance and adsorption mechanism of heavy metal Pb²⁺were studied.The adsorbent was used for selective adsorption and resource recovery of Pb²⁺in lead containing wastewater.Humic acid was extracted from Zhaotong Lignite by alkali solution and acid precipitation.The functional groups of humic acid were modified by sulfomethylation reaction.Lignite humic acid sulfonated resin（SHA-PF）was obtained by crosslinking and curing of sulfonated humic acid and phenolic resin under the combined action of hydrochloric acid and high temperature.The optimal solidification temperature was300℃.Scanning electron microscopy（SEM）,energy dispersive X-ray spectroscopy（EDS）,Fourier transform infrared spectroscopy（FTIR）and mercury porosimetry experiments showed that the sulfonic groups were well retained in the structure of SHA-PF after high temperature curing.The average pore size of sha-pf was 889.4 nm,the porosity was 54.71%,and there were many adsorption pores;Sha-pf has rough surface,complex and irregular pore structure.The optimal solid-liquid ratio of SHA-PF for adsorption of Pb²⁺is 0.8 g/L,and the optimal pH value of the solution is 5.It follows the quasi second order reaction mechanism,and chemical reactions such as chelation,coordination and complexation occur;The maximum adsorption capacity q_max was 617.3 mg/g;SEM,FTIR and XPS analysis showed that the sulfonic group and carboxyl group in the structure of SHA-PF took part in the coordination reaction after contacting with the solution containing heavy metal Pb²⁺,and Na⁺and Ca²⁺on the surface of SHA-PF also exchanged with Pb²⁺in the solution during the adsorption process.For single and mixed heavy metal ion systems(Pb²⁺,Cu²⁺,Cd²⁺),fixed other conditions unchanged,single change of SHA-PF and heavy metal ion contact time,solution pH value and initial ion concentration and other conditions,SHA-PF has fast adsorption rate,large adsorption capacity and strong adsorption stability for Pb²⁺.The simulated real water body was used to explore the adsorption.For tap water and Pb²⁺mixed solution,SHA-PF successfully reduced the concentration of Pb²⁺below the national standard of 10 mg/m L;In the simulated acid mine wastewater,the removal rate of Pb²⁺was still 92.7%.The adsorption desorption cycle experiment showed that0.1 mol/L EDTA solution was more suitable for SHA-PF regeneration,and the removal rate of Pb²⁺remained at 84.3%when the reuse times reached four times..In this paper,cheap and easily available humic acid was modified to use as adsorbent material to improve the selectivity and adsorption capacity of humic acid for heavy metal Pb²⁺.The process cost is low and the operation is simple.While turning humic acid waste into treasure,the pollution of lead containing wastewater is treated and the recovery and utilization of Pb²⁺is realized,which provides a new way to realize the high value utilization of humic acid.This paper consists of 40 figures,8 tables and 95 references.