工程科学与技术2025，Vol.57Issue(3)：299-309,11.DOI:10.12454/j.jsuese.202300637
聚丙烯酰胺/假酸浆复合材料制备及其对刚果红的吸附性能
Preparation and Adsorption Performance of Polyacrylamide/Nicandra Physalodes(L.)Gaertn Composite Material for Congo Red Removal
摘要
Abstract
Objective The discharge of various organic pollutants has caused significant water pollution issues over the past decades.Congo red,a widely used and highly hazardous dye,presents challenges in degradation and treatment.Therefore,it is imperative to explore the development of an effi-cient,non-polluting,and convenient post-treatment adsorbent for Congo red in wastewater. Methods A composite adsorbent was created using Nicandra physalodes(L.)Gaertn,polyacrylamide(PAM),and expanded graphite to adsorb Congo red from dye wastewater.The solubility of Nicandra physalodes(L.)Gaertn seeds enabled the extraction of surface gums through a con-ventional distilled water extraction method.The resulting Nicandra physalodes(L.)Gaertn seed gum(NPG)was prepared using freeze-drying and vacuum-drying.Expanded graphite was modified through the neutralization reaction of strongly acidic ferric chloride hexahydrate and so-dium hydroxide.Simultaneously,ethylene glycol was used as a co-solvent and catalyst in the reaction,yielding modified graphite with magnetic properties.The synthesis,which involved the dissolution and compounding of NPG,PAM,and modified graphite,was followed by injection into a configured calcium chloride solution and freeze-drying to produce the composite adsorbent.Characterization was conducted using scanning electron microscopy,Fourier transform infrared spectroscopy(FTIR),and zeta potential analysis,and the adsorption mechanism was examined. Results and Discussions Static adsorption experiments were conducted to investigate the influence of solution pH,adsorbent dosage,adsorption time,temperature,and initial concentration on the adsorption performance for Congo red.The equilibrium concentration,adsorption capacity,and removal rate were determined through transmittance detection.Isothermal analysis employed the Langmuir and Freundlich models;kinetic analy-sis involved pseudo-first-order,pseudo-second-order,and intraparticle diffusion models;and thermodynamic analysis calculated parameters to un-derstand the adsorption behaviors and mechanisms of the composite adsorbent on Congo red.Corresponding experiments were performed to as-sess the reusability of the composite adsorbent.Material characterization indicated that NPG had a relatively dense and smooth surface,with a three-dimensional spatial mesh gel structure formed in Ca2+ion solution.The incorporation of modified graphite resulted in a composite adsor-bent with a rough and porous surface,folds,a long strip-like structure,and grooves,providing numerous active sites for Congo red adsorption.The zeta potential of the composites was positive under acidic conditions(pH<7)and negative under alkaline conditions(pH>7).The results of the static adsorption experiments demonstrated the commendable adsorption capacity of the composites for Congo red(CR).pH was identified as the primary factor influencing the composites·performance in CR adsorption.The composite·s effectiveness in adsorbing CR is improved in acidic and neutral solutions but decreases under alkaline conditions.At pH 7,the equilibrium adsorption capacity of CR peaked at 89.6％,while a significant decline was observed as the pH increased from 7 to 10,reducing the removal rate from 89.6％to 3.6％.In dosage experiments,with an initial solution concentration of 80 mg/L,increasing the composite dosage from 6 to 18 mg enhances the CR removal rate from 76.5％to 86.6％.The time experiment identified two distinct stages in the adsorption process when the initial solution concentration was 100 mg/L and the compos-ite dosage was 100 mg.From the start to 286 minutes,the adsorption capacity reached 138.52 mg/g,and after 826 minutes,it plateaued at an equi-librium adsorption capacity of 168.96 mg/g.In temperature and concentration experiments,within the range of 303 to 323 K,the adsorption per-formance of the composites on CR declines with increasing temperature,while the equilibrium adsorption capacity increases with the initial con-centration.The fitting results of the adsorption kinetic models indicated that the pseudo-first-order model best represents the adsorption process.Adsorption isotherm fitting results showed better alignment with the Freundlich isotherm model,suggesting that CR adsorption by composites oc-curs on non-uniform surfaces through multilayer adsorption driven primarily by electrostatic interactions and hydrogen bonding.Thermodynamic analysis confirmed that CR adsorption by composites is a spontaneous exothermic process.In reusability experiments,the equilibrium adsorption capacity and CR removal rate of the composites showed a modest decline of 16.32％and 13.7％,respectively,after five adsorption-desorption cycles,remaining at a high level.This demonstrates the good reusability of the prepared composite adsorbents. Conclusions The developed composite adsorbent in this study exhibits robust adsorption performance for CR.Its simple fabrication process,envi-ronmentally friendly and readily available raw materials,and the feasibility of solid-liquid separation via magnetism support its potential applica-tion in CR removal from dye wastewater,providing valuable insights for the selection and preparation of adsorbents.关键词
假酸浆/聚丙烯酰胺/改性石墨/吸附性能/刚果红Key words
Nicandra Physalodes(L.)Gaertn/polyacrylamide/modified graphite/adsorption performance/Congo red分类
环境科学引用本文复制引用
郭万金,孙浩,曹雏清,赵立军..聚丙烯酰胺/假酸浆复合材料制备及其对刚果红的吸附性能[J].工程科学与技术,2025,57(3):299-309,11.基金项目
中国博士后科学基金项目(2024M760002) （2024M760002）
中央高校基本科研业务费专项资金项目(300102253201) （300102253201）
