The role of biochar properties in influencing the sorption and desorption of Pb(II), Cd(II) and As(III) in aqueous solution
The role of biochar properties in influencing the sorption and desorption of Pb(II), Cd(II) and As(III) in aqueous solution
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DOI：
10.1016/j.jclepro.2017.01.125
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发表时间：
2017-04
影响因子：
11.1
通讯作者：
Eric F. Zama;Yong-guan Zhu;B. Reid;Gou-Xin Sun
中科院分区：
文献类型：
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作者：
Eric F. Zama;Yong-guan Zhu;B. Reid;Gou-Xin Sun
研究了350、450、550和650 °C下制备的20种生物炭的化学和物理性质，以确定它们在3种潜在有毒元素（Pb、Cd、As）的吸附和解吸中所起的关键作用。利用扫描电子显微镜、傅里叶变换红外光谱、X射线衍射和X射线光电子能谱对生物炭表面进行了研究。有机官能团（如单键COOH、C双键O、C单键X）、无机矿物（CaCO 3、SiO2、Ca 2Si 5 O 10·3 H2O）和阳离子（K+、Ca 2+、Mg 2+、Na+）对PTE的吸附有显著的控制作用，而物理性质（形貌、比表面积）对潜在有毒元素的吸附影响不大。四种主要机制解释了所有20种生物炭对Pb（II）的异常高的吸附（97.5-99.8%），而Cd（II）和As（III）的吸附（分别<90%和42%）仅由两种机制（沉淀和静电吸引）控制。热力学研究表明，大部分生物炭对Pb和Cd的吸附是自发的吸热行为，而As的吸附也是吸热的，但不是自发的。吸附的PTE被观察到在宽范围的pH值（3.5-9.5）内非常稳定，解吸范围为0.2至16.5%。详细了解生物炭表面性质如何与PTE相互作用，增加了开发具有特殊吸附特性的成本效益和工程生物炭的可能性。
The chemical and physical properties of 20 biochars produced at 350, 450, 550 and 650 °C were investigated to determine the key roles they play in the sorption and desorption of three potentially toxic elements (Pb, Cd, As). Biochar surfaces were studied using scanning electron microscopy, Fourier transform infra-red spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Organic functional groups (e.g. single bondCOOH, Cdouble bondO, Csingle bondX), inorganic minerals (CaCO3, SiO2, Ca2Si5O10·3H2O) and cations (K+, Ca2+, Mg2+, Na+) controlled PTE sorption significantly while physical properties (morphology, surface area) showed little influence on the sorption of potentially toxic elements. Four major mechanisms accounted for the exceptionally high Pb(II) sorption by all 20 biochars (97.5–99.8%) while Cd(II) and As(III) sorption (<90% and 42% respectively) were controlled by two mechanisms (precipitation and electrostatic attraction) only. Thermodynamic studies suggested that Pb and Cd sorption on a majority of biochars was spontaneous and endothermic while As sorption was also endothermic but not spontaneous. Sorbed PTEs were observed to be very stable over a wide range of pH values (3.5–9.5) with desorption ranging from 0.2 to 16.5%. Detailed understanding of how biochar surface properties interact with PTEs increases the possibility of developing cost effective and engineered biochars with exceptional sorption characteristics.