摘要：

铬具有优异的物理和化学性能，被广泛用于机械制造、金属冶炼、印刷、有机合成、电镀等行业，由此产生大量含Cr（Ⅵ）的废水和废渣，对人类和环境构成危害。以FeCl₃·6H₂O、AlCl₃·6H₂O、Na₂HPO₄·6H₂O为原料制备了聚磷氯化铝铁（PPAFC）复合混凝剂，研究其对含Cr（Ⅵ）废水的混凝沉降效果，并用SEM、XRD、FT-IR进行表征。SEM结果表明PPAFC表面为不定型晶体，截面较完整；XRD谱图出现PPAFC各个物相的特征衍射峰，峰形较尖锐，结晶度较好；FT-IR光谱表明磷酸根与聚合氯化铝铁（PAFC）发生接聚，生成新的物相。当PPAFC投加量为1.5 g、温度为30℃、废水质量浓度为15 mg/L、pH为9时，PPAFC对Cr（Ⅵ）的去除效果最佳，去除率可达92.96%。PPAFC混凝去除Cr（Ⅵ）主要基于压缩双电层、吸附电中和、吸附架桥和沉淀物网捕等机理。

关键词: 聚磷氯化铝铁, 混凝剂, Cr（Ⅵ）

Abstract:

Chromium has excellent physical and chemical properties, and is widely used in manufacturing, metal refinery, printing, organic synthesis, electroplating and other industries, resulting in a large number of wastewater and waste residue containing Cr(Ⅵ), which is harmful to human and environment. The composite coagulant polymeric phosphato aluminum-ferric chloride(PPAFC) was prepared from FeCl₃·6H₂O, AlCl₃·6H₂O and Na₂HPO₄·12H₂O. The coagulation sedimentation treatment effect on wastewater containing Cr(Ⅵ) was researched, and the characterizations were analyzed by SEM, XRD and FT-IR. SEM results showed that the surface of PPAFC was an amorphous crystal with a relatively complete cross-section. XRD showed that the characteristic diffraction peak of PPAFC appeared. The peak shape was sharp and the crystallinity was good. The FT-IR spectra showed that the phosphate group bonded with polyaluminium ferric chloride(PAFC) to form a new phase. Under the condition of PPAFC dosage 1.5 g, temperature 30℃, wastewater mass concentration 15 mg/L, pH 9, PPAFC had the best removal effect, and the removal rate reached 92.96%. Coagulation to remove Cr(Ⅵ) by PPAFC was mainly based on the electric double layer compression, adsorption electric neutralization, adsorption bridging and sedimentation net mechanism.

Key words: polymeric phosphato aluminum-ferric chloride, coagulant, Cr(Ⅵ)

中图分类号: 

• X703