改性玉米芯磁性重金属吸附剂的制备与吸附性能研究

Study on Preparation and Its Adsorption Performance for Modified Corncob Magnetic Adsorbent of Heavy Metals

重金属废水进入环境难以降解,严重影响到水环境、土壤环境,甚至人类健康。因此,废水中重金属的去处迫在眉睫。玉米芯本身具有良好的亲水特异性和丰富活性基团,对重金属离子等能有效的吸附。本研究以玉米芯为原料,通过物理化学改性,探索最佳的改性制备方法,获得了玉米芯改性磁性重金属吸附材料,采用SEM、XRD、IR对其吸附材料的表面形态及微观结构进行观测与分析,研究了最佳的吸附条件,探索了吸附热力学、动力学等理论。研究结果显示,最佳的制备条件为氮气保护下加酸pH调节至4,震荡1 h,加氯化镁20%,亚铁与铁30%,氢氧化钾调节pH为11,温度50℃,震荡3 h后,过滤烘干后马弗炉450℃保持2.5 h;SEM、XRD、IR结果显示改性后获得的磁性重金属吸附材料微观结构发生了变化,提高了吸附效率;最佳使用条件为pH为5,常温下最佳的吸附时间2 h,最佳适用浓度Pb和Zn≤150.0 mg/L,Cd、Cr、Cu最佳适用浓度≤100.0 mg/L,最佳的投加量为20 g/L;获得的改性玉米芯磁性重金属吸附材料吸附符合准二级动力学模型,为物理吸附,属于吸热反应。所制备的改性玉米芯磁性重金属吸附剂对重金属离子具较高的吸附性能,是一种绿色、廉价、易回收的重金属吸附材料,有望用于重金属离子废水的处理。

Heavy metal wastewater is difficult to degrade when it enters the environment,which seriously affects the water environment,soil environment and even human health.The disposal of heavy metals in wastewater is urgent.Corncob itself has good hydrophilic specificity and rich active groups,which can effectively adsorb heavy metal ions.In this study,the corncob was used as raw material to explore the best modification preparation method through physical and chemical modification,and corncob modified magnetic heavy metal adsorption material was obtained.SEM,XRD and IR were used to observe and analyze the surface morphology and microstructure of adsorbed materials.The optimum adsorption conditions were studied,and the theories of adsorption thermodynamics and kinetics were explored.The results showed that the optimal preparation conditions were:nitrogen protection with acid adjusted to pH 4,shock for 1 h,magnesium chloride 20%,ferrous and iron 30%,potassium hydroxide adjusted to pH 11,after shock for 3 h,temperature 50 ℃,filtration and drying at 450 ℃ Muffle furnace for 2.5 h;SEM,XRD and IR showed that the microstructure of the modified magnetic heavy metal adsorption material changed,and the adsorption efficiency was improved.The best use conditions are pH 5,the best adsorption time 2 h at room temperature,the best suitable concentration of Pb and Zn≤150.00 mg/L,the best suitable concentration of Cd,Cr and Cu≤100.00 mg/L,and the best dosage of 20 g/L.The adsorption of the modified corn cob magnetic heavy metal adsorption material conforms to the quasi-second-order kinetic model and is a physical adsorption,which belongs to the endothermic reaction.The prepared modified corncob magnetic heavy metal adsorbent has high adsorption performance for heavy metal ions,and is a green,cheap and easy to recover heavy metal adsorption material,which is expected to be used in the treatment of heavy metal ion wastewater.