Xu S, Gong X F, Zou H L, Liu C Y, Chen C L, Zeng X X
School of Resource Environmental and Chemical Engineering, Nanchang University, Nanchang 330031, China E-mail:
Water Sci Technol. 2016;73(2):396-404. doi: 10.2166/wst.2015.475.
In this study, we exhibit the recycling of agriculture wastes of ramie stalk as bioadsorbents for Cd(2+) removal. Based on our experimental results, it is realized that Cd(2+) adsorption to ramie stalk is highly pH sensitive, indicating the adsorption is driven by surface complexation reaction. The high adsorption capacity of ramie stalk toward Cd(2+) (qm = 10.33 mg g(-1), 0.09 mol-Cd g(-1)), which corresponds to around 21.95% of active adsorption sites available of ramie stalk, is believed to be closely related to its high cellulose and lignin content. The inhomogeneous surface of ramie stalk due to the high cellulose and lignin content also accounts for the observation that the adsorption kinetic is described well by the pseudo second order kinetic model. Results from thermodynamic studies suggest that the adsorption process is endothermic and spontaneous. All these properties demonstrate the potential of ramie stalk as a low cost bioadsorbent for the application of heavy metal removal.
在本研究中，我们展示了将苎麻茎农业废弃物作为生物吸附剂用于去除Cd(2+)的循环利用。基于我们的实验结果，认识到苎麻茎对Cd(2+)的吸附对pH高度敏感，表明该吸附是由表面络合反应驱动的。苎麻茎对Cd(2+)具有较高的吸附容量（qm = 10.33 mg g(-1)，0.09 mol-Cd g(-1)），这相当于苎麻茎约21.95%的可用活性吸附位点，据信这与其高纤维素和木质素含量密切相关。由于高纤维素和木质素含量导致苎麻茎表面不均匀，这也解释了吸附动力学能用准二级动力学模型很好描述这一现象。热力学研究结果表明吸附过程是吸热且自发的。所有这些特性都证明了苎麻茎作为一种低成本生物吸附剂用于去除重金属的潜力。
