Preparation And Application Of Molecularly Imprinted Chitosan In Water Treatment

Aminated porous chitosan imprinting microspheres (AP-CSMIP) was preparedby microwave radiation technology. Through out single factor experiment and or-thogonal experiment of the hole, amino protection, grafting more amino groups,s-uch as molecularly imprinted preparation process, it is concluded that AP-CSMIPto optimize the preparation process, It was used to treat wastewater which wascontaining heavy metal ions.The adsorption capacity was taken as the main eval-uation index, studied the AP-CSMIP adsorption of Cu2+conditions, selective ads-orption of metal ions, mixed solution multiple metal ions adsorption separation a-dsorption thermodynamic analysis and kinetic analysis on Cu2+and the adsorbentrecycling experiments were studied.The results shows that,1)The preparation conditions of AP-CSMIP were opt-imized through out single factor experiment and orthogonal experiment, the struc-ture of the adsorbent was characterized by SEM and FT-IR, and AP-CSMIP sho-wed good sphericity, mean diameter was0.97mm, a lot uneven groove were onthe surface, which greatly increased the surface area of the AP-CSMIP and impr-oved its adsorption capacity.2)The effect conditions for Cu2+adsorpted on AP-CSMIP such as pH, AP-CSMIP dosage, initial metal ion concentrationand oscillati-ontime were studied, the best condition is:0.07g AP-CSMIP was added into300mg/LCu2+solution (25mL), the pH was adjusted to5.0, oscillate for8h, the a-dsorption capacity could reach48.46mg/g.3)The adsorption mechanism for AP-CSMIP to Cu2+was studied, the adsorption data was fitted by thermodynamic a-nd kinetic models and results show that the adsorption of Cu2+AP-CSMIP beha-vior better conform to the Langmuir isotherm model (R2>0.9928), the adsorptionprocess is given priority to with chemical adsorption, according to the adsorptionenthalpy change>0, Entropy change S>0, Free energy change G <0, the resuit shows that the adsorption process is a spontaneous, unordered, endothermicchemical adsorption process.4)In the binary ions mixture system, the adsorption sel-ectivity for Cu2+adsorpted on AP-CSMIP was studied, the results shows that therelative selectivity coefficient is greater than1,the selective adsorption of AP-CSMIP is higher than AP-CS, which showed that the AP-CSMIP for Cu2+has astr- ong adsorption selectivity. The adsorption order for AP-CSMIP adsorpted metalions were Cu2+>Ni2+, Cu2+>Pb2+.5)Using the AP-CSMIP specific selectivity furt-her investigation of Cu2+AP-CSMIP for binary and ternary containing Cu2+ionsadsorption separation of heavy metals in the mixed system, in the Cu2+/Ni2+sys-tem, after five times separation that Cu2+can be completely isolated; In the Cu2+/Pb2+system, after five times separation that Cu2+can be completely isolated; Inthe Cu2+/Ni2+/Pb2+system, after five times separation that Cu2+can be completelyisolated.6)AP-CSMIP in0.1mol/L HCl solution regeneration, after five times ofreuse, the adsorption capacity still be92.01%of the original, indicating that ithas great adsorption regeneration performance.7)Compared with a variety of dif-ferent adsorbent the adsorption capacity of AP-CSMIP is greatly higher, compare-d with the non-imprinted adsorbent, AP-CSMIP adsorption quantity increaseof ne-arly21.27%, has high practical value.The study of the preparation of AP-CSMIP can provide theoretical and pract-ical basis for develop a kind of heavy metal sorbent which is selectivly, renewa-ble and efficient separation.