木质素磺酸钠吸附材料的制备及对刚果红的吸附性能

Preparation of sodium lignosulfonate adsorption materials and their adsorption properties for Congo red

【目的】以木质素磺酸钠(SLS)为原料,制备胺化改性的木质素磺酸钠以及共价有机框架聚合物/胺化木质素磺酸钠复合材料,考察它们作为吸附材料对刚果红的吸附性能。【方法】木质素磺酸钠与甲醛、二乙烯三胺经曼尼希反应制得胺化木质素磺酸钠(ASLS),采用红外光谱(FTIR)和扫描电镜(SEM)对吸附剂的表面官能团和形貌进行了表征。考察刚果红起始质量浓度、ASLS用量、溶液pH、吸附时间等对材料吸附效果的影响;探究ASLS的吸附动力学和循环再生性能。制备富含醌共价有机框架聚合物(AQ-COF),对比ASLS、AQ-COF、AQ-COF/ASLS材料对刚果红的吸附效果。【结果】FTIR和SEM表征结果显示:木质素磺酸钠成功胺化,ASLS与AQ-COF复合后自组装成棒状纳米结构。ASLS吸附结果表明:刚果红起始质量浓度为200 mg·L^(-1),ASLS用量为70 mg,pH为1~5时,吸附率达95%以上,并在80 min内达到吸附平衡,吸附过程符合准二级吸附动力学模型和Langmuir等温吸附模型,吸附过程主要为化学吸附。30 mg ASLS中添加少量AQ-COF(2 mg),复合吸附剂吸附率可达80%以上。【结论】胺化改性木质素磺酸钠对刚果红有良好的吸附效果,且具有优秀的再生性能,可以作为刚果红的优良吸附剂;共价有机框架聚合物AQ-COF与ASLS复合制备的复合吸附剂可以提升ASLS对刚果红的吸附能力,表明共价有机框架聚合物在刚果红吸附领域有良好的应用前景。

[Objective]Aminated sodium lignosulfonate(SLS)and covalent organic framework polymer/aminated sodium lignosulfonate composites were prepared with SLS as raw materials,and their adsorption properties for the Congo red(CR)were investigated.[Method]Aminated sodium lignosulfonate(ASLS)was prepared by Mannich reaction of sodium lignosulfonate with formaldehyde and diethylenetriamine.The surface functional groups and morphology of ASLS were characterized by infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).The effects of initial concentration of CR,ASLS dosage,the pH value of the solution,and the adsorption time on the adsorption efficiency of the materials were investigated.The adsorption kinetics and regeneration performance of ASLS were analyzed.The AQ-COF was prepared,and the ASLS,AQ-COF,AQ-COF/ASLS on the adsorption for CR was compared.[Result]FTIR and SEM characterization results showed that sodium lignosulfonate was successfully aminated,and rod-like nanostructures were self-assembled after the combination of ASLS and AQ-COF.ASLS adsorption experiment showed that when the initial concentration of CR was 200 mg·L^(-1),the dosage of ASLS was 70 mg,and the pH was 1−5,the adsorption rate reached above 95%,and adsorption equilibrium was achieved within 80 minutes.The adsorption process was in line with the quasi second order adsorption kinetics model and Langmuir isotherm adsorption model,and the adsorption process was mainly chemical adsorption.When a small amount of AQ-COF(2 mg)was added to 30 mg ASLS,the adsorption rate of the composite adsorbent could reach more than 80%.[Conclusion]The modified aminated lignin has good adsorption effect on CR and excellent regeneration property,which can be used as an excellent adsorbent for CR.The composite adsorbent prepared by combining covalent organic framework polymer AQ-COF with ASLS can significantly improve the adsorption capacity of ASLS for CR,indicating that covalent organic frame polymers have good application prospects in the adsorption of organic pollutant CR.