Preparation Of Protien-based Composites And Its Study In Removing Heavy Metal Ions From Water

Massive amounts of toxic,non-degradable and bioaccumulation heavy metal ions are discharged directly to natural water bodies,which pose a significant threat.So,it is urgent to remove heavy metal ions from water.Due to its simple operation,strong universality and low investment cost,removal of contaminants by adsorption become an effective way.Photocatalytic technology driven by sunlight is an alternative or supplement to adsorption methods,showing great potential in water pollution control.However,the current absorbents have low adsorption capacity and poor separation properties.Photocatalysis also has a limited range of light responses and poor degradation efficiency.In this study,natural biomass(bovine serum albumin)was used as raw material to prepare aerogels and photocatalytic nanoparticles.Those protein-based composite materials exhibited excellent removal ability of heavy ions in water.(1)Bovine serum albumin was treated to be amyloid fibrils,and then amino-functionalized bovine serum albumin amyloid fibrils(BFP-based)aerogels with properties of ultra-light,easily separable,and stable for adsorption were constructed by crosslinking with branched poly ethyl eneimine.Finally,those aerogels were utilized to remove Cu(Ⅱ)from water.The maximum adsorption capacity of the aerogel for Cu(Ⅱ)was 82.7 mg/g,which was 3.01 times the adsorption capacity of pure protein aerogel.The entire process of Cu(Ⅱ)adsorption on aerogels was well described by the Freundlich model and pseudosecond-order kinetics.The result of the adsorption mechanism indicated that the adsorption behavior of aerogels for Cu(Ⅱ)is greatly influenced by complexation,electrostatic interaction and reduction.The aerogels also show excellent adsorption ability to a variety of heavy metal ions and organic pollutants.The adsorption performance and stability of the aerogels were improved by introducing and cross-linking with branched polyethyleneimine,which provides a reference for Cu(Ⅱ)removal from water.(2)The Nitrogen-doped carbon quantum dots/TiO2 nanoparticles with excellent photocatalytic performance were synthesized by a one-step hydrothermal method using bovine serum albumin and tetrabutyl titanate as raw materials.The removal efficiencies of Cr(Ⅵ),Congo red and Escherichia coli by N-doped carbon quantum dots/TiO2 under simulated sunlight were over 99.9%.Moreover,the bovine serum albumin nanofibers/N-CQDs/TiO2 composite film was constructed,and it shows a 99.9%reduction efficiency for Cr(Ⅵ)and also contains a 80%reduction efficiency after 3 recycles.This result demonstrates that the composite film has good photocatalytic performance and recycling.Bovine serum albumin exerts its potential as a biomass carbon material,effectively improving the photocatalytic reduction of Cr(Ⅵ)by TiO2,and also uses Bovine serum albumin amyloid fibrils good mechanical properties to construct photocatalytic composite film,which provides valuable reference for the practical application of photocatalytic reduction of Cr(Ⅵ).