木质垃圾与废铁泥制备Fe0-BC材料及其去除水中Cr(VI)
Preparation of Fe0-BC using wood waste and iron mud and its application for removing Cr(VI)
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摘要: 含铬废水的直接排放会对自然环境造成严重危害。为探究零价铁-生物炭材料(Fe0-BC)与Cr(Ⅵ)的反应效能,以木质垃圾与印染行业废铁泥两种亟需处理的固体废物作为原料,在不同温度下通过碳热还原制备Fe0-BC,并将其应用于水中Cr(Ⅵ)的去除。材料表征结果表明,1 200 ℃下制备的Fe0-BC材料性能最佳,其比表面积为105.6 m3/g,孔径为6.23 nm,物相主要由Fe0、Cu0、C以及少量杂质构成,其中Fe0以球状的颗粒形式分散附着在碳的孔结构中,且大小均匀,粒度基本达到纳米级。通过静态试验考察了Fe0-BC材料对Cr(Ⅵ)的去除过程,结果表明Fe0-BC-1200对Cr(Ⅵ)的去除效果最好,在初始浓度为20 mg/L、初始pH为3.5、投加量为2.5 g/L的条件下,去除率能达到95.2%。Cr(Ⅵ)的去除过程符合准二级反应动力学过程和Langmuir方程(R2>0.99),最大吸附量为10.71 mg/g。Cr (Ⅵ)的去除是包含吸附、还原以及络合沉淀等共同作用的结果,此外,Cu0的存在有利于催化Fe0的氧化,从而促进Cr(Ⅵ)的去除。研究显示,利用固体废物制备的Fe0-BC材料成本低且对于含Cr(Ⅵ)废水的解毒效果显著,是实现“以废治废”的环境治理新思路。Abstract: Chromium containing wastewater is seriously hazardous to the natural environment if it is being discharged directly. In order to explore the reaction efficiency of zero-valent iron/biochar (Fe0-BC) and Cr (Ⅵ), the Fe0-BC was synthesized by the carbothermal reduction of wood waste and printing and dyeing industry iron mud at different temperatures and applied in the removing of Cr(Ⅵ) in aqueous. The characteristics of Fe0-BC were detected by specific surface area analyzer and scanning electron microscope (SEM), and the results indicate that the Fe0-BC-1200 prepared at 1200 °C has the best performance with a specific surface area of the Fe0-BC is 105.6 m3/g and a pore diameter of 6.23 nm. The physical phases of Fe0-BC-1200 are mainly composed of Fe0, Cu0, C and a few number of impurities, and the Fe0 particles are dispersed and attached inside the pore structure of carbon as spherical particles with a uniform size distribution at the nanometer level. Furthermore, the removal process of Cr (Ⅵ) by Fe0-BC was studied by batch experiments. The Fe0-BC-1200 shows the best removal performance, which the removal ratio of Cr (Ⅵ) can reach 95.2% under the conditions of initial concentration of 20 mg/L, initial pH value of 3.5 and dosage of 2.5 g/L. The removal process of Cr (Ⅵ) is well predicted by the pseudo-second-order model and Langmuir equation (R2> 0.99), and the maximum adsorption capacity is 10.71 mg/g. The removal mechanisms mainly include adsorption, reduction and complex precipitation. In addition, the presence of Cu0 is beneficial to catalyze the oxidation of iron, thus promoting the removal of Cr (Ⅵ). The Fe0-BC prepared by solid waste has the advantages of low cost and significant detoxification effect on Cr (Ⅵ) wastewater containing, which is a new idea to realize the purpose of ‘dealing pollution with waste’.
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Key words:
- Wood waste /
- Iron mud /
- Carbothermal reduction /
- zero-valent iron/biochar /
- Cr (VI)
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