赤泥在沼液除磷中的应用

采用工业废物赤泥去除沼液中磷酸盐,利用XRF、XRD、PSD和SEM等手段对赤泥基本物理化学性质进行了综合表征,研究了沼液初始pH(pH_i)、赤泥投加量、反应时间和初始磷浓度等因素对沼液中磷酸盐去除率和沼液最终pH(pH_f)的影响。结果表明:沼液中磷酸盐去除率随着pH_i的增加呈先降低后增加趋势;磷酸盐去除率最大值和最小值分别出现在pH_i为2.1和6.9处,分别为89.6%和47.2%;赤泥投加量越大、反应时间越长,磷酸盐去除率越高,pH_f越大;而初始磷浓度越低,磷酸盐去除率越高,pH_f越大。采用3 ⁴水平正交试验设计考察了各因素间的交互作用及对赤泥除磷的影响,得到赤泥除磷的最佳条件:pH_i为10.0,赤泥投加量为5.0 g/L,初始磷浓度为1.7 mg/L,反应时间为40 min。

Study on phosphorus removal from biogas slurry by red mud

The red mud(RM), an industrial waste of alumina production, was applied to remove phosphorus from biogas slurry. The XRF, XRD, PSD and SEM tests were employed to assess the physicochemical properties of RM. Some important parameters that affect the phosphorus removal efficiency and final pH of solution(pHf), such as initial pH(pHi), RM dosage, reaction time and phosphate concentration of biogas slurry were explored. The results indicated that the phosphate removal efficiency decreased first, and then increased with the increase of pH. And the highest and the lowest phosphate removal efficiency were 89.6% and 47.2%, under the conditions of pHi 2.1 and 6.9, respectively. The RM dosage and contact time had a positive effect, whereas initial phosphate concentration had a negative effect on phosphate removal and pHf. The effects of individual variables on phosphate removal were determined by using a 3 4 orthogonal experiment design. The results showed that the optimal reaction conditions were as follows: pHi 10.0, RM dosage 5.0 g/L, initial phosphate concentration 1.7 mg/L, and contact time 40 min.