给水污泥酸提液改性活性炭纤维吸附磷性能的研究

Study on phosphorus adsorption performance of activated carbon fiber modified by acid extract of waterworks sludge

随着社会的高速发展,水体富营养化问题日趋严重,磷的过量排放是导致水体富营养化的关键诱因。采用给水厂污泥为主要原材料制备污泥酸提液(Sae),以活性炭纤维(ACF)为载体、Sae为改性溶液,制备吸附材料Sae-ACF。结果表明,Sae-ACF在水中具有良好的稳定性;当温度为25℃、磷初始质量浓度为10 mg/L、Sae-ACF投加量为1 g/L、pH=7、反应时间为60 min时,Sae-ACF对磷的去除率为95.11%,比ACF提高了52.92%;经过4次循环再生后,Sae-ACF对磷的去除率仍可达56.25%。吸附机理研究表明:Sae-ACF对磷的吸附过程符合准二级动力学模型、Elovich模型及Freundlich等温吸附模型,吸附过程为自发进行的多分子层化学吸附,升高温度有利于反应的发生。SEM与XRD结果表明,Sae-ACF表面紧密包裹着一层Al_(2)O_(3)、Fe_(2)O_(3)和FeO(OH)晶体,吸附过程中这些晶体与磷发生反应生成了AlPO_(4)与FePO_(4)沉淀。

With the rapid development of society,the eutrophication of water is becoming more and more serious,and the excessive discharge of phosphorus is the key factor of eutrophication of water.The sludge acid extract(Sae)was prepared using water supply plant sludge as the main raw material.The adsorption material Sae-ACF was prepared using activated carbon fiber(ACF)as the carrier and Sae as the modified solution.The results showed that Sae-ACF had good stability in water.Under the conditions of 25℃of temperature,10 mg/L of the initial mass concentration of phosphorus,1 g/L dosage of Sae-ACF,pH=7,and 60 min of the reaction time,the phosphorus removal rate of Sae-ACF was 95.11%,which was 52.92%higher than that of ACF.After four cycles of regeneration,the phosphorus removal rate by Sae-ACF was still up to 56.25%.The adsorption mechanism study showed that the adsorption process of phosphorus by Sae-ACF was in accordance with the quasi-second-order kinetic model,Elovich model and Freundlich isothermal adsorption model.The adsorption process was spontaneous chemical multi-molecular layer adsorption,and increasing the temperature was conducive to the occurrence of the reaction.SEM and XRD results showed that the surface of Sae-ACF was closely wrapped with a layer of Al_(2)O_(3),Fe_(2)O_(3) and FeO(OH)crystals,which reacted with phosphorus during the adsorption process to form AlPO_(4) and FePO_(4) precipitation.