Study On The Synthesis Of Cyclodextrin Derivatives And The Adsorption Performance For Removal Of Heavy Metals And Dyes

During the past decades,heavy metal wastewater has increased from various industrial activities such as smelting,electroplating,painting,mining,leather tanning.And heavy metals?such as Cd????are commonly used as mordants in the dyeing process,so dyes and heavy metals are commonly found in dye wastewater.And in many wastewater treatment methods,the adsorption method has high practical value because of its high efficiency,low cost and low cost.In this study,it was used as the main body of the?-cyclodextrin??-CD?,and the reaction was modified by xylacylation to synthesize the?-cyclodextrin-sodium xanthogenate??-CDX?,which was used to remove Pb???from the wastewater.And the crosslinking polymer bifunctional adsorbent were fabricated by an easy and green approach through the polycondensation reaction of?-CD with mercaptosuccinic acid?MA?,citric acid?CA?as the crosslinker,for simultaneous adsorption of metals and dyes.The structure and morphology of the materials were characterized by ¹³C NMR,SEM,EDS,FTIR and XPS.The results show that the materials have high potential in water treatment because of its high adsorption capacity and high stability.In the study of the adsorption experiment of the?-CDX material used in lead-containing wastewater.The results demonstrated that the optimal removal effect for Pb???was achieved when?-CDX was used rather than using lime alone,the maximum removal rate of the Pb???ions was 98%for all initial concentrations and the products were larger and looser at an optimum pH range from 9 to 12.The characterization analysis indicates that the RC?S?SNa in?-CDX is the main contributor to the chelation of the Pb???.MA-?-CD and CA-?-CD applied to heavy metals and dyes molecular adsorption experiment.In a single pollutant system,the adsorption quantity of two kinds of material increases with the increase of pH for CD???and MB,but little impact on pH on the adsorption of a MO.The dynamic experimental data of Cd???,MB and MO accord with the quasi-second-order kinetic equation,indicating that the adsorption process mainly focuses on chemical adsorption,and the adsorption process mainly focuses on surface adsorption.Process of Cd???adsorption isotherm model experiments accord with the Langmuir model,and the material surface was distribution,and absorbs heavy metal ions easily.Process of Cd???adsorption isotherm model experiments,Sips model has higher goodness of fit,explainning one of the active site of the cavity plays a dominant role,while the rest of the active site?-SH,-COOH and-OH?in the adsorption also play a bigger role for MB and MO adsorption.According to the calculation of thermodynamic parameters,the adsorption process both are endothermic reactions.In the mixed system,MB will competition the adsorption sites?-SH,-COOH and-OH?with Cd???which can lead to Cd???and MB adsorption quantity are reduced.But in a mixture of anionic dye MO and Cd???system,two kinds of pollutants is not the same adsorption sites,and MO can provide extra for Cd???adsorption sites,Cd???at the same time can able to neutralize the material surface electrical promote the adsorption of MO,therefore,MO and Cd???adsorption quantity in the mixed system will promote each other.