壳聚糖活性污泥复合吸附剂的制备研究

Preparation of composite adsorbent with chitosan and activated sludge

为了提高污泥细胞吸附重金属离子的应用能力,采用壳聚糖包埋固定活性污泥,制备了粒径2~3 mm的壳聚糖活性污泥复合吸附剂SCTS.以吸附溶液中CrO2-4的吸附率为指标,通过单因素实验对制备过程中采用的2种固化液及5种发泡剂进行比选,考察了固化液浓度、发泡剂量、交联剂量、活性污泥与壳聚糖用量比值及发泡温度对SCTS吸附能力的影响,由正交实验确定影响因素主次顺序及最优水平组合.结果发现,固化液浓度、发泡剂量、污泥与壳聚糖用量比值及发泡温度对SCTS吸附能力影响较强,影响次序为固化液浓度>发泡剂量>活性污泥与壳聚糖用量比值>发泡温度.最优水平组合为4 g·L-1三聚磷酸钠(STPP)固化液、剂量为吸附剂质量10%的NH4HCO3发泡剂、活性污泥与壳聚糖用量比值0.5、发泡温度100℃,此时CrO2-4吸附率最高可达97.3%.该吸附剂的制备研究为污泥的资源化利用探索了新的途径.

In this study,one type of composite adsorbent called SCTS was produced to enhance the effect of heavy metal adsorption by sludge cells.SCTS consists of chitosan and activated sludge with the size of 2 ~ 3 mm.The adsorption rate of CrO2-4was selected as the key index in the single factor experiment to evaluate two kinds of candidate curing agent and five kinds of foamer.Five factors were examined to ascertain the effects on the adsorption capacity of SCTS,which include curing solution concentration,dosage of foamer,amount of cross-linking agent,ratio between activated sludge and chitosan and foaming temperature.The principal-secondary sequence of factors and the optimal level combination were deduced by orthogonal experiment.The results revealed that the selected factors have significant effect on the adsorption capacity of SCTS and the sequence of influential factors is:dosage of curing agent,dosage of foamer,ratio between active sludge and chitosan,and then foaming temperature.The adsorption rate of CrO2-4has achieved 97.3%under the condition:4 g·L-1STPP,10% NH4HCO3,sludge-to-chitosan ratio 0.5,and foaming temperature 100 ℃.The present study can be a reference for innovation of residual sludge utilization.