Modification of Natural Polymer and Its Application in Wastewater Treatment of Heavy Metal Ions
|School||Northwest Normal University|
|Keywords||Natural polymer Bentonite Straw cellulose Acrylic acid Adsorbent Heavy metal ions from wastewater|
In recent years, people attach great importance to the study of heavy metals in waste water treatment, developed many kinds of treatment methods to remove heavy metals from wastewater. Natural polymer and their derivatives adsorbent in addition to a rich source, non-toxic, biochemical degradation process is simple, lower-cost advantages due to the diversity of its structure and molecular activity groups selectively than modified prepared structure, it is easy to diverse to apply different range of polymer adsorbent. This thesis the bentonite, straw cellulose, acrylic acid was prepared from a heavy metal ion adsorbent for lead, copper and other wastewater treatment, has a very important practical significance. First, the modified bentonite, bentonite and its modified products in the heavy metal wastewater treatment method modified cellulose, cellulose and its modified products in the heavy metal wastewater treatment progress, and at the same time summarizes the bentonite, cellulose, modified existing problems. Second, sulfuric acid calcium bentonite, acrylic acid as raw materials, prepared bentonite complexes of polyacrylic acid / sulfuric acid (PAA / HB), and based on the removal of Pb 2 sup> to determine polyacrylic acid / sulfuric acid bentonite optimal preparation conditions; were characterized by FT-IR, TG / DTA, XRD, SEM its structure and morphology. Third visits polyacrylic acid / sulfuric acid of Bentonite complex (PAA / HB) adsorption of metal ions (Pb 2 sup>, Cu 2 sup>) removal performance and mine drainage COD removal efficiency: 1) the use of polyacrylic acid / sulfuric acid bentonite complexes containing Pb simulated wastewater 2 sup> adsorption treatment, under the best conditions, namely: [of Pb 2 < / sup>] starting at 500 mg / L, adsorbent dosage of 1 g / L, pH of 5.0,20 oC with shaking for 60 min, Pb 2 sup> removal rates up to 99.9% , residual concentration is lower than the national emission standard; The adsorption kinetics characteristics comply with the quasi-second-order kinetic model, and other adsorption isotherm model is in good agreement with the Langmuir isotherm equation. 2) the use of polyacrylic acid / sulfuric acid bentonite complex adsorption treatment of wastewater containing Cu 2 sup>, the removal rates of up to 97.8%, the best treatment conditions: [Cu 2 sup>] start 200 mg / L, adsorbent dosage of 1 g / L, pH 6.0,20 oC with shaking for 60 min; adsorption dynamics in line with quasi-second-order kinetics. model, the adsorption isotherm model fit the Langmuir isotherm. 3) the use of polyacrylic acid / sulfuric acid bentonite complexes COD removal efficiency of the actual mine drainage, and the results showed that the mine drainage solution by acid associated with coagulation and sedimentation clarification 100 mL at 20 oC adsorbent dosage 0.025 g, pH 5.0, and the shock speed of 100 r / min and shaken for 2 min, the treatment was best, COD removal efficiency of up to 78.9%. Fourth, basified bleaching carboxymethylation wheat straw cellulose and acrylic graft polymerization of polyacrylic acid / wheat straw cellulose composite adsorbent (PAA / WSC), by FT-IR, TG / DTA, SEM its structure and morphology characterization; investigated containing Pb 2 sup> wastewater adsorption treatment under optimal conditions, ie: [Pb 2 sup>] start 600 mg / L, adsorbent dosage of 1 g / L, pH of 5.0,20 oC with shaking for 60 min, Pb 2 sup> The removal rates of up to 99.8%, the residual concentration is lower than the national emission standards; The adsorption kinetics characteristics comply with the quasi-second-order kinetic model, and so the Langmuir adsorption isotherm model isotherm.