Optimized Preparation Of Thiosemicarbazide-cellulose Composite Materials For Water Treatment

The rapid development of industrialization has led to a series of environmental pollution problems,such as the increasing discharge of factory wastewater.In these industrial wastewaters,most of them contain excessive heavy metal ions and solid suspended solids,which causes great troubles for the wastewater treatment stage of the enterprise.In the current wastewater treatment process,adsorption and flocculation precipitation are the two most effective methods for treating pollutants in wastewater.There are many kinds of materials for adsorption and flocculation on the market,and the treatment effect on pollutants is also uneven.The most widely used materials are organic materials,among which natural polymer materials are biodegradable,inexpensive and environmentally friendly that have been widely concerned by researchers.Cellulose is abundant in nature and belongs to natural high molecular substances.In this study,one biodegradable thiosemicarbazone-cellulosematerial?BPC-g-TSC?was synthesized by one-step method using cellulose abundant in nature and thiosemicarbazide and cross-linked by cross-linking agent glutaraldehyde.The adsorption properties of composite materials on several different metal ions and the flocculation effect on kaolin suspension were investigated.Finally,the actual wastewater was initially treated.The following results were obtained:?1?Preparation and performance characterization of thiosemicarbazone-cellulose:In order to optimize the preparation process,a five-factor and four-level orthogonal experiment was designed to obtain the optimal preparation process of adsorptionand flocculation materials according to the range analysis:TSC dosage was 1g/g,the amount of glutaraldehyde used was0.375 g/g,the reaction time was for 5 h,the reaction temperature was at 60°C,and the pH=4.The morphology of BPC-g-TSC was analyzed and proved that the thiosemicarbazone-cellulose was successfully prepared.After degradation for 10 days in the soil extract at 37°C,the degradation rate was 40.2%and the degradation rate in 80 days was 78.8%,indicating the BPC-g-TSC material prepared by the experiment has good biodegradability.?2?Adsorption performance of thiosemicarbazone-cellulose on different metal ions:by investigating the effects of adsorption pH,adsorption time,adsorbent dosage and initial concentration of adsorbate on the adsorption properties of BPC-g-TSC materials,determine the adsorption effect of thiosemicarbazone-cellulose on heavy metal ions.By analyzing adsorption kinetics and adsorption isotherm model for the adsorption of three metal ions,indicates that adsorption process for Cr⁶⁺,Cu²⁺and Sb³⁺ions is more consistent with the Langmuir model and single-layer surface adsorption.?3?Study on the flocculation performance of thiosemicarbazone-cellulose on kaolin suspension:The Zeta potential of BPC-g-TSC and kaolin suspension at different pH was tested.The factors such as different pH,flocculation time and material dosage were investigated forthe influence of the turbidity.The optimized flocculation effect was pH=4,and the turbidity was 10.9 NTU.After 5 min of flocculation treatment,the turbidity of the supernatant began to decrease by 151 NTU.25 min later,the turbidity of the supernatant reached an equilibrium state at 11.5 NTU.The good effect exhibited by the flocculation treatment of kaolin solution indicated that the flocculation time is fastand it is expected to be applied to the actual wastewater.?4?The adsorption capacity of composite water treatment materials for Cr⁶⁺and Cu²⁺in electroplating wastewater was 74.31 mg/g and 47.26 mg/g,respectively.The turbidity removal rate of electroplating wastewater was 86.6%;the adsorption amount of Sb³⁺in printing and dyeing wastewater reached 83.57 mg/g,the turbidity removal rate was 85.0%.In this paper,a simple and feasible preparation method is provided.Cellulose is used as raw material,and thiosemicarbazide is used as a monomer to synthesize an adsorbent flocculating material,which exhibits good treatment effect on heavy metal ions and solid suspended solids,and it is expected to be applied in large scale.It also provides more ideas and theoretical support for future water treatment materials.