Fabrication Of PPy-based Biomaterials And Its Adsorption/Desorption Behavior Of Acid Fuchsin In Water

Biomass material is an environmentally friendly and easily degradable matrix material,and has good applications as an adsorbent for water pollutants.In this paper,several kinds of biomass materials（sodium carboxymethyl cellulose,gelatin,chitosan,straw）with a wide range of sources and low prices are selected as raw materials,and modified by adding polypyrrole（PPy）to prepare biomass-based PPy nanocomposites.All show excellent adsorption performance for acid fuchsin（AF）.In addition,excellent conductivity and photothermal properties of PPy are used to make the prepared nanocomposite materials capable of desorption with the assistant of light and electricity,reducing the reliance of the adsorbent on high concentration acid-base eluents While improving the recycling of the adsorbent,it also avoids possible secondary environmental pollution.The main research contents are as follows:1.Two inexpensive and renewable biological resources,gelatin（Gel）and carboxymethyl cellulose（CMC）,were crosslinked by nanostructured PPy to achieve a novel PPy-hydrogel.The morphology and composition of the CMC/Gel/PPy hydrogels were characterized.The result shows that the CMC/Gel solution can provide an excellent condition for the dispersion of PPy.Based on the combination of PPy and the biomass matrix,specific adsorption sites can be formed by the synergistic effect of the functional groups derived from CMC,Gel and PPy.The CMC/Gel/PPy hydrogel has an exclusive adsorption of AF.Furthermore,the adsorption process of AF on the CMC/Gel/PPy hydrogel was investigated,and influencing factors,such as adsorbent dosage,temperature,initial dye concentration and adsorbent recyclability,were discussed in detail.Under optimal conditions,the CMC/Gel/PPy hydrogel can reach an adsorption equilibrium within 50 minutes in a 60 mg/L AF solution at 24℃,and the AF removal efficiency was approximately 94%.It was also observed that the AF removal efficiencies of CMC/Gel/PPy remained almost unchanged after at least seven consecutive adsorption–desorption cycles.2.PPy was dispersed into two inexpensive and renewable biomass materials,Gel and Chitosan（CS）,to fabricate a novel photo/electric-sensitive hydrogel Gel/CS/PPy.The morphology and composition of the Gel/CS/PPy hydrogels were characterized by SEM and FTIR.The results show that Gel/CS/PPy hydrogel has the most adsorption efficiency of AF at p H 6.5,was 94.2%,and basically does not adsorb the other four dyes.The entire adsorption process is due to chemical adsorption caused by electrostatic attraction.Furthermore,with addition of PPy,Gel/CS/PPy has the characteristic of photo/electric response,which can improve the elution efficiency of AF from adsorbent.The experimental data shows that that the elution efficiency could be increased by 4 times with photo-assistance,and by about 2times with electro-assistance.3.The pyrrole was uniformly dispersed in the straw（STR）waste solution and oxidized in situ using ammonium persulfate（APS）as an oxidant to form STR_R/PPy,STR_A/PPy,STR_A/E/PPy composite materials.Morphological analysis and functional group analysis of obtained three composites were performed by depth-of-field digital microscope and FTIR.Dye adsorption experiments showed that the three composites had specific adsorption on acid fuchsin.Among three composites,STR_R/PPy exhibit higher adsorption efficiency.Furthermore,the factors involved in the adsorption process such as temperature,initial dye concentration and p H were investigated.The results showed that the STR_R/PPy composite could reach adsorption equilibrium within 40 min at 28℃in 60 mg/L AF solution,and the AF removal efficiency was approximately 89%.In this paper,PPy with nanostructure is effectively dispersed in the biomass matrix to maintain the nano-characteristics and stability of PPy and promote the macro application of nanomaterials.The prepared optical/electrically sensitive biocomposite materials not only have low cost but high selectivity.In addition,it can also carry out targeted transformation for different pollutants,which has a good reference for the treatment of water pollutants.