Mussel Inspired Preparation Of Catechol-amine Composite Materials And Their Removal Properties Towards Cr(Ⅵ)

Inspired by the adhesion between the catechol group and the amino polymer in the polydopamine mussel adhesive protein,the surface of the composite material was multifunctional by taking advantage of the easy modification of polydopamine.During the study we use the amine and phenolic hydroxyl groups,the mechanism of polymerization between the design such as polyethylene glycol（PEG@PTHA）@poly phenol amine,polyamine,alkali lignin-pyrocatechol（PCEA-AL）and polyamine sodium lignosulfonate-polyethylene amine,these three phenolic amino by using environmental scanning electron microscope（SEM）,energy spectrum analysis（EDS）,Fourier transform infrared spectrometer（FT-IR）,thermo-gravimetric analyzer（TGA）,Ultraviolet spectrophotometer（UV-visible spectroscopy）and X-ray photoelectron spectroscopy（XPS）,and other instruments characterization methods analysis the apparent morphology and surface functional groups of the sample,we choose the removal of hexavalent chromium ion as adsorbent performance standards,the experimental conditions including contact time,initial concentration,adsorbent dosage,temperature and coexistence of competition and a series of variables for the influence of adsorption performance,and through thermodynamic model,dynamic model for the data from the experiment of linear fitting,and further discuss the reaction mechanism involved in the adsorption.This thesis is divided into three parts.（1）To the suction filter purification of alkali lignin under the condition of 95℃by the crosslinking effect of formaldehyde was prepared with divinyl three amine amination alkali lignin,the preparation of good amination alkali lignin with pyrocatechol under the condition of weak alkaline reaction,which was a very remarkable new adsorbent towards Cr（VI）removal.Confirming its removal ability through a series of variables,the stick together coral shaped adsorbent has the largest adsorption capacity is 640 mg/g,and in 10 min can adsorption at an astonishing 300mg/g,In a certain low initial concentration of Cr（VI）ionic solution,the removal rate is close to 100%.The experimental data are in good agreement with the quasi-second-order kinetic model and the Langmuir isothermal adsorption model,indicating that the whole adsorption process is monolayer adsorption,and the adsorption kinetics is more serious.The external anion weakens the adsorption property.In conclusion,PCEA-Al is an excellent adsorption material that can quickly adsorb Cr（VI）ions in simulated wastewater.（2）And a second job processing methods are similar,the same to the suction filter purification of sodium lignosulphonate under the condition of same is 95℃,with formaldehyde crosslinking of polyethylene imine amination reaction obtained lignin,late to join the catechol,at room temperature and weak alkaline 48 h,under the condition of reaction was poly（sodium lignosulfonate-polyethylene imine-pyrocatechol）adsorbent,and by using various experimental variable to explore the influence of different conditions on adsorption performance,and this is also the coral shaped adsorbent has the largest adsorption capacity is 655 mg/g,under the condition of low initial concentration,the removal amount is close to 100%.According to experimental data fitting,the correlation coefficient between Langmuir isothermal adsorption model and quasi-second-order kinetics is closer to 1,which means that the fitting degree is higher,and it also indicates that the adsorption kinetics is dominated by monolith adsorption and chemisorption.In conclusion,poly（sodium lignosulfonate-polyethylenimine-cataphene）is a synthetic adsorbent with remarkable removal effect.（3）In this study,the adsorption microspheres with rough surface structure（PEG@PTHA）were successfully prepared by adding the mixture of PEG and HA into the above-mentioned tannic acid solution in 50m L ultra-pure water,which was used as an adsorbent for the treatment of Cr（VI）wastewater.At a low initial concentration（100mg/L）,the removal rate was close to 99%,and the maximum adsorption capacity was450 mg/g.The adsorption process is more consistent with the quasi-second-order kinetic model and the Langmuir isotherm model.In the adsorption process,there is not only physical adsorption,but also chemical adsorption.Toxic Cr（VI）is reduced to harmless Cr（III）,and PEG@PTHA shows an efficient competitive adsorption of Cr（VI）on anions(NO^-and SO4^2-).PEG@PTHA Adsorption agent has the advantages of convenient preparation,high selectivity and low cost.It has a good application prospect in the treatment of Cr（VI）containing wastewater,and combined with the results of XPS analysis,it can be confirmed that there is a REDOX effect and electrostatic attraction effect in the removal process of Cr（VI）ions,which is also the main reaction mechanism of the adsorption process.Polyphenolamine composites containing a large number of amino and phenolic hydroxyl groups have the advantages of low cost,easy synthesis and operation,strong applicability and more efficient adsorption capacity,which has great potential in the treatment of Cr（VI）ion wastewater.