载镧生物炭的优化制备及其对水体中砷的吸附

以玉米秸秆为原材料优化制备用于吸附水体中五价砷的载镧生物炭(La-biochar),对其表面进行了系统表征,同时考察了环境条件对载镧生物炭吸附性能的影响.结果表明:相比负载前生物炭,负载后生物炭表面更粗糙,比表面积增大4.6倍,同时表面成功负载有大量镧元素.以获取对五价砷的最大吸附能力为目的,通过响应面模型获得La-biochar的优化制备条件为:物料比w(La)/w(秸秆)=9.47%,停留时间=20min,热解温度=300oC.中性和酸性环境条件有利于La-biochar对砷酸根的吸附,而碱性条件则有不利影响;较高浓度的CO32-显著降低其对砷酸根吸附,而同样浓度的Cl-和F-不会造成明显影响.

Optimized preparation of lanthanum uploaded biochar and its application in adsorbing pentavalent arsenic ions from aqueous solution

Lanthanum uploaded biochar (La-biochar) that utilized for removing pentavalent arsenic ions from aqueous solutions was prepared on the basis of corn straw. The operation conditions during production procedure of La-biochar were optimized, and then La-biochar was characterized. Compared with control biochar (CK), the surface of La-biochar was rougher, and specific surface area increased 4.6 times. XRF Results showed La-biochar possessed an amount of lanthanum. Through response surface method, the optimized preparation parameters for the maximum adsorption capacity of pentavalent arsenic ions were obtained, and the parameters were as follows: material ratio (w (La)/w (straw) )= 9.47%, residence time = 20min, pyrolysis temperature = 300oC. Both Acid conditions and neutral conditions were preferable for adsorbing arsenic ions, while alkaline conditions would decrease the removal efficiency of arsenic ions. The effect of three negative ions (CO32-, F-, and Cl-) on the adsorbing process was investigated, and results showed that only high concentration of CO32- could decrease the removal efficiency of pentavalent arsenic ions. Through the production of La-biochar, several goals were achieved, including the reutilization of corn straw, reduction of lanthanum consumption, and dramatically increase of the adsorption capacity of pentavalent arsenic ions from aqueous solutions.