针对搬迁化工场地遗留高色度地下水处理过程中存在的色度来源不明、处理水量较大、需原地处理等问题,采用共沉淀法制备水滑石,并使用壳聚糖进行改性,脱除化工场地遗留高色度地下水色度.利用扫描电镜(SEM)、比表面积分析仪(BET)和傅里叶变换红外光谱仪(FT-IR)分析材料,研究色度脱除的原理,通过动力学和热力学实验,验证色度脱除的效果.分析表明,改性水滑石材料孔隙结构发达,层状结构清晰,与未改性水滑石相比吸附速率快、容量高,是有效的色度脱除材料.吸附前后的红外光谱对比与C1-浓度实验表明,脱色的机理包括表面吸附、离子交换、表面微絮凝等3种作用;在pH值为7,药剂投加量为0.3g/L,反应温度为25℃,反应时间为2h的条件下,废水色度的脱除率可达90％.处理1m3该类高色度地下水,总处理成本约为4.9元,价格较低,处理单位可接受.

采用共沉淀法制备锌铁水滑石类(LDH),并使用十二烷基硫酸钠(SDS)对其进行改性.利用比表面积与孔径分析、扫描电镜与透射扫描电镜、X射线衍射、傅立叶变换红外光谱和多功能电子能谱等手段分析材料,研究材料的改性机制,通过动力学和热力学实验,验证材料的吸附效果.结果 表明,锌铁LDH材料孔隙结构发达,层状结构清晰,改性后的材料层间距扩大,吸附容量进一步提高,是更为优秀的吸附材料.对于Cr(Ⅳ)的质量分数30 mg/g的溶液,改性后的锌铁LDH吸附剂优化投加量为0.2～0.4 g/L;溶液pH对除铬效果影响较大,pH为4时吸附效果最好;反应温度较高时除铬效果较好.改性后的锌铁LDH吸附剂对Cr(Ⅳ)的最大吸附容量可达到117 mg/g.

Zn‐Fe layered double hydroxide with chloride intercalation (ZFCL) was synthesized by a coprecipitation method at room temperature. ZFCL was characterized by N2 adsorption‐desorption isotherms, X‐ray diffraction, scanning electron microscope, Zeta‐sizer analyzer, X‐ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The results showed that ZFCL had large surface area and layered structure. The maximum adsorption capacity of ZFCL was 150.6 mg/g at 25°C. That was higher than most other adsorbent which were reported. The kinetic data were described better by the pseudo‐second‐order adsorption kinetic rate model. The adsorption isotherm on the adsorbent was described by Langmuir, Freundlich, and Sips models at pH 6 and followed the fitting order: Sips >Freundlich>Langmuir. Thermodynamic analyses indicated that the phosphate adsorption on ZFCL was endothermic and spontaneous in nature. The sequence of coexisting cations and anions competing with phosphate was Ca2+ > Mg2+ > Na+ and SO42− > NO3− > Cl−. ZFCL can be regenerated by the sequential use of NaOH and ZnCl2. The adsorption capacity remained high as 108.6 mg/g after regeneration of 3 times. The results of zeta potential, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy analyses indicated that the phosphate adsorption mechanisms involved ion exchange, Zn3(PO4)2 precipitation, and the formation of inner‐sphere complex via replacement of surface hydroxyl groups by phosphate.

采用共沉淀法制备Zn-Fe-LDH,利用扫描电镜(SEM)、X射线衍射仪(XRD)和傅立叶变换红外光谱仪(FT-IR)分析材料,研究材料的吸附原理,通过动力学和热力学实验,验证材料的吸附效果.分析表明,Zn-Fe-LDH材料孔隙结构发达,层状结构清晰,与Mg-Al-LDH材料(传统水滑石)相比吸附速率快、容量高,是更为优秀的吸附材料.吸附前后的红外光谱对比及共存离子影响实验证明了有磷酸根离子在离子交换作用下进入LDH;材料用量0.5 g/L,处理质量浓度30 mg/L磷溶液,处理时间2h,此时Zn-Fe-LDH对磷的去除率可达到96.26％;溶液pH对除磷效果影响较大,而常见共存离子的影响较小.

The effectiveness of RAS degradation under low dose ozone and effect of ozonated sludge on a full scale anaerobic-anoxic-aerobic (A/A/O) process were examined. The ratios of chemical oxygen demand (COD) to nitrogen and COD to phosphorus of ozonated sludge were 23 and 91 respectively on average, much higher than in influent. Compared with the performance of A/A/O process alone, COD removal efficiency slightly decreased after insertion of the ozonation system. Ammonia removal became more stable, but total nitrogen and total phosphorus removal efficiency was not improved. Sludge volume index (SVI) of activated sludge reached to an optimal value of 80-120 mL/g quickly due to ozonation combined with A/A/O process which reduced the danger of sludge bulking. Overall, the combination of biological process with ozonation at a low dose rate shows promise. Compared with higher dose ozonation, low-dose ozonation can improve the performance of A/A/O effectively at a smaller cost.