荔枝壳活性炭对Cr(Ⅵ)吸附性能的研究-《电镀与精饰》

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Title:: Studies on the Adsorption Performance of Lychee Exocarp Activated Carbon on Cr( Ⅵ)

摘要:: 以荔枝壳为原料,氢氧化钠为活化剂、微波加热,制备了荔枝壳活性炭。并以此活性炭为吸附剂吸附溶液中的Cr(Ⅵ),考察了初始Cr(Ⅵ)质量浓度、活性炭用量、pH、吸附时间、吸附温度对Cr(Ⅵ)的吸附量及去除率的影响。结果表明吸附Cr(Ⅵ)的最佳工艺条件为:荔枝壳活性炭质量1.6 g/L、Cr(Ⅵ)初始质量浓度50 mg/L、pH=3、吸附θ为25℃、吸附t为240 min,在此工艺条件下,荔枝壳活性炭吸附剂对Cr(Ⅵ)具有良好的吸附能力,对Cr(Ⅵ)吸附量可达30.25mg/g,Cr(Ⅵ)的去除率可达96.8%。吸附过程符合二级吸附动力学模型。热力学参数ΔG、ΔH、ΔS表明荔枝壳活性炭对Cr(Ⅵ)的吸附过程是自发、吸热过程。

Abstract:: The activated carbon was prepared using lychee exocarp as raw material,NaOH as activating agent and microwave as heating source. Effects of initial mass concentration of Cr( Ⅵ),quantity of activated carbon,pH,adsorption time,adsorption temperature on the adsorption quantity and removal rate of Cr( Ⅵ)were investigated using the prepared lychee exocarp activated carbon as adsorbent. The results showed that the optimal conditions were as follows: the initial Cr( Ⅵ) mass concentration was 50 mg / L,activated carbon dosage was 1. 6 g / L,pH was 3,temperature was 25 ℃ and adsorption time was 240 min. Under the conditions,the prepared lychee exocarp activated carbon showed good adsorption performance to Cr( VI) and its adsorption quantity and removal rate of Cr( VI) could reach 30. 25 mg / g and 96. 8%,separately. The adsorption reaction was consistent with the second order kinetic equation and the thermodynamics values ofΔG,ΔH and ΔS indicated that the adsorption process was spontaneous and endothermic.