| 氧化镁基生物质炭高效去除水体中磷的特性 |
| 摘要点击 2449 全文点击 849 投稿时间：2016-11-16 修订日期：2017-02-07 |
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| 中文关键词 氧化镁 磷 生物质炭 吸附 应用 |
| 英文关键词 magnesium oxide phosphate biochar adsorption application |
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| 中文摘要 |
| 利用花生壳为前驱体，在高温限氧条件下，将氧化镁（MgO）负载于生物质炭（BC）表面制备出氧化镁基生物质炭（MgO-BC）复合材料.系统研究了MgO-BC对水体中P的吸附特性，并探讨了溶液pH值、接触时间、竞争离子等因素对P的吸附效果的影响.结果表明，P的最佳吸附初始pH为7~9，过酸过碱的环境均不利于P的吸附；P的吸附过程可在540 min内达到平衡，且动力学曲线较好地符合伪一级和伪二级动力学模型，拟合系数可达97.3%和99.0%；当Cl-、HCO3-、NO3-等共存离子的量浓度达到P的10倍时，MgO-BC对P仍具有较强的吸附能力；P的吸附过程较好地符合Langmuir等温模型，拟合系数达99%，理论最大吸附容量为138.07 mg·g-1，远高于其它未经改性或改性的生物质炭和几种典型P吸附剂的吸附容量.此外，吸附P后的复合材料可作为肥料施入土壤，可有效实现P的再利用.综上所述，该MgO-BC复合材料在净化实际P污染水体中有着广阔的应用前景. |
| 英文摘要 |
| A novel composite material MgO-biochar (MgO-BC) with the peanut shells as the precursors was successfully fabricated by loading magnesium oxide (MgO) on the surface of biochar (BC) at high temperature and in oxygen-limited atmosphere. The adsorption characteristics of the resultant adsorbent toward phosphate from aqueous solution were investigated by evaluating the influences of pH, contact time and coexisting ions. The results showed that the best phosphate adsorption onto MgO-BC happened in the pH range of 7-9, and strong acidic or basic media was unfavorable to the phosphate adsorption. Phosphate adsorption process could reach equilibrium within 540 min, and the kinetics curve could be well fitted by both pseudo-first and pseudo-second models. The related coefficients were 97.3% and 99.0%. MgO-BC exhibited highly selective capacity toward phosphate in the presence of competing Cl-, HCO3- and NO3- at 10 times higher concentration than the phosphate concentration. In addition, phosphate adsorption onto MgO-BC could be described satisfactorily by Langmuir model with a fitting coefficient of higher than 99%, and the maximal adsorption capacity calculated by Langmuir equation was 138.07 mg·g-1. The adsorption capacity of phosphate by MgO-BC was much higher than the unmodified BC and other biochar-based sorbents. Furthermore, the composite material after the adsorption of phosphate could also be used as a fertilizer into the soil. It achieved the reuse of the discarded phosphate. All the results validated that MgO-BC has a wide application prospect for the phosphate cleanup from the actual wastewater. |
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