Preparation And Adsorption Performance Of The Modified Poly(Catechol-amine) And Its Composite

Inspired by the principle of self-polymerization of dopamine and its application of adhesion and adsorption properties,the modified poly?catechol-amine?materials andpoly?catechol-amine?compositematerials,includinglignin-based poly?catechol-amine?adsorbents?PCEA-LS?,Fe₂O₃-based poly?catechol-amine?composite?Fe2O3@Cc-PAA?and?Congo red-polyallylamine?@catechol-hexamethylenediaminehybridmaterial??PAH-CR?@PCHA?were designed and prepared in this paper.And the microscopic morphology and structure of these materials were characterized and analyzed by the use of environmental scanning electron microscopy?SEM?,Fourier transform infrared spectrometer?FT-IR?,thermogravimetric analysis?TGA?,X-ray photoelectron spectroscopy?XPS?,etc.Furthermore,the adsorption performance was evaluated using heavy metal ions?Cr????or dyes?CR?as adsorbates,and the influence of various factors on their removal ability were investigated,including pH value,adsorbents dosage,time.,temperature,initial concentration and so on.Finally,the isothermal adsorption model,kinetic equations,intraparticle diffusion model,thermodynamic equations were used to fit the experimental data and explore the adsorption mechanism.This dissertation can be divided into three parts:?1?Preparation and characterization of lignin-based poly?catechol-amine?adsorbent?PCEA-LS?and its adsorption performance to Congo red dye in unadjusted pH solution.The characterization test demonstrated that the PCEA-LS particles were successfully prepared according to the design scheme.Adsorption experiments showed that the adsorption time of PCEA-LS adsorbed Congo red reached the equilibrium was 12 h.This process was affected by the particle dispersion model,and spontaneous and endothermic.It conformed to the Langmuir isothermal adsorption and pseudo-second-order kinetic models.The maximum theoretical adsorption capacity at303 K was 1052.6 mg/g.Lignosulfonate is not only widely sourced and inexpensive,but also exhibits high adsorption performance by using it to modify poly?catechol-amine?.It is a very promising adsorbent.?2?Removal of Cr???by Fe₂O₃@Cc-PAA composites from simulated wastewater.Inspired by the adhesion properties of polydopamine,Fe₂O₃@Cc-PAA composites were prepared by one-step method and used to remove Cr???from the solution.A series of adsorption experiments were carried out under the conditions of pH=2.0 and pH=6.5.The results showed that the adsorption behaviors at both pHs were in accordance with the Langmuir and pseudo-second order kinetic equations,and the maximum theoretical adsorption capacity of pH=2.0 and pH=6.5 at 303 K were 633 mg/g and 112.1 mg/g,respectively.Therefore,the adsorbent can be applied to the removal of hexavalent chromium in certain types of wastewater and daily drinking water.?3?The?PAH-CR?@PCHA adsorbent was successfully obtained by flocculation from Congo red solution.The adsorbent can not only be easily prepared from dye wastewater,but also can effectively uptake Cr???from simulated wastewater.The maximum adsorption capacity calculated by the Langmuir model at 30°C was 282.42 mg g^-1.The kinetic data showed good correlation with pseudo second-order equations.Negative?G°and positive?H°indicated that the adsorption process is spontaneous and endothermic.The modified/composite poly?catechol-amine?were not only prepared under mild and simple conditions,but also rich in monomer sources and various types.The molecular structure of adsorbents can be designed production or grafted modification according to the requirments.What'more,poly?catechol-amine?adsorbent have high adsorption amount,good cycle performance,low cost in the removal of pollutants,and broad development prospects and application values in the future.