酸度对好氧颗粒污泥生物吸附含铅废水影响的研究
Effect of acidity on biosorption of Pb2+ wastewater by aerobic granular sludge
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摘要: 为了有效地控制铅污染，利用序批式反应器（sequencing batch reactor,SBR）培养的以醋酸钠为碳源的好氧颗粒污泥作为吸附剂，进行生物吸附含铅废水的效能和机理的研究。通过考察酸度、接触时间和Pb2+初始浓度等因素的影响，验证好氧颗粒污泥吸附模型，并利用不同的脱附剂，进一步解析其生物吸附的Pb2+。实验结果表明, 酸度是影响好氧颗粒污泥生物吸附Pb2+的关键因素，当初始pH为5时，好氧颗粒污泥对含铅废水生物吸附效果最好。对低浓度（0～20 mg/L）含铅废水， 10 min后可快速达到吸附平衡。好氧颗粒污泥对Pb2+的实测饱和吸附量为101.97±9.00 mg/g，符合朗缪尔（Langmuir）模型。好氧颗粒污泥生物吸附Pb2+的过程，伴随着pH值的升高和K+、 Ca2+、 Mg2+的释放，此现象揭示离子交换作用是好氧颗粒污泥生物吸附Pb2+的机理之一。此外，脱附剂HNO3、EDTA和CaCl2能实现Pb2+的回收和好氧颗粒污泥的重复利用。Abstract: In order to control the pollution of lead，aerobic granular sludge cultivated in sequencing batch reactor（SBR）was used for the treatment of wastewater containing Pb2+. The influences of acidity, contact time and initial Pb2+ concentration were investigated in batch experiments, and the biosorption model and mechanism were also analyzed. The results of the experiments show that acidity is an important factor in Pb2+ biosorption by aerobic granular sludge. When the initial pH is 5, aerobic granular sludge has the best Pb2+ biosorption efficiency. Moreover，biosorption equilibrium occurs within 10 min at each initial Pb2+ concentration in the range of 0～20 mg/L. The actual biosorption capability of Pb2+ by aerobic granular sludge is 101.97±9.00 mg/g. The Langmuir equation is in good agreement with the experimental data of Pb2+ biosorption by aerobic granular sludge. During the process of Pb2+ biosorption, pH increases and K+，Ca2+，Mg2+ are released, which implies that ion exchange is one of Pb2+ biosorption main mechanisms. Besides, the recovery of Pb2+ with desorbents, HNO3, EDTA and CaCl2, allows the reuse of aerobic granular sludge.
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Key words:
- aerobic granular sludge /
- Pb2+ /
- ion exchange /
- biosorption /
- desorption
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