Oxidative Extraction,Composition Structure And Adsorption K~+ Performance Of Shengli Brown Coal Humic Acid

In this paper,the effect of experimental conditions on the yield of humic acid extracted from raw coal and oxidized brown coal was studied with Shengli lignite as raw material.The material composition of humic acid products was analyzed by spectroscopy,thermogravimetry,infrared spectroscopy and gas phase mass spectrometry.The humic acid extracted from lignite was used as the adsorbent in different treatments.The static adsorption experiment was carried out on the laboratory simulated K~+containing wastewater.The ion adsorption performance of lignite humic acid was studied and the kinetics of humic acid adsorption was simulated.Research indicates:(1)The total acidity of the three groups of humic acid of raw coal humic acid(YF),hydrogen peroxide lignite humic acid(GF),nitric acid oxidized brown coal humic acid(XF)increased in turn,and the carboxyl content increased in turn,while the two oxidized humic acids were compared.It was found that the phenolic hydroxyl group content was similar,and the XF carboxyl group content was significantly increased because the nitric acid was oxidized in a large amount to form a carboxyl group.(2)The types of substances contained in the three types of lignite humic acid are generally the same,but the proportion of various substances has obvious differences.Compared with GF and XF,the proportion of alcohol phenols and ether compounds in YF is larger.The ketones and carbonyl compounds in the two types of oxidized brown coal humic acid have a greater specific gravity.This phenomenon indicates that the oxidation operation converts the alcohol phenols and ether compounds of the humic acid component in the lignite into ketones and carbonyl compounds.At the same time,nitric acid oxidizes brown coal humic acid to produce amide or heterocyclic N species.(3)By comparing the results of gas-mass spectrometry experiments,it can be found that the oxidation operation significantly increases the kinds of oxygen-containing functional groups in the humic acid,and at the same time changes the oxygen-containing functional groups from alcohols and aldehydes to higher-order ketones,esters and carboxylic acids.However,hydrogen peroxide oxidation converts the oxygen-containing functional groups in humic acid into ketones,furans,esters,but the oxygen-containing functional groups in the original raw coal humic acid do not disappear;and the oxidation of nitric acid converts the oxygen-containing functional groups in the humic acid into ketones.,furan,carboxylic acid,and the original aldehydes in the original coal humic acid disappeared.(4)The humic acid extracted from lignite was used as the adsorbent under different treatment methods.The static adsorption experiment was carried out on the laboratory simulated K~+containing wastewater to study the ion adsorption performance of lignite humic acid.The adsorption kinetics of humic acid was simulated by Elovich kinetic model,Lagergren quasi-first-order kinetic model and Lagergren quasi-secondary kinetic model.