Wei Yanxin, Cheng Xueqing, Ding Aimin, Xu Juncui
College of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China.
ACS Omega. 2020 Sep 29;5(40):26094-26100. doi: 10.1021/acsomega.0c03625. eCollection 2020 Oct 13.
A magnesium silicate polymeric coagulant (MgSiPC), which is an inorganic polymer for dye removal from wastewater, was prepared with different pH by copolymerization. The acidity was a key factor in the preparation of the MgSiPC. In the present research, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to analyze the characterization of optimum coagulants. Additionally, the response surface method (RSM) was applied to optimize the process of coagulation-flocculation. The results of FT-IR and XRD implied that the main components of the MgSiPC with pH 1.50-2.50 were almost the same. SEM images showed that MgSiPCs with pH 1.50-2.50 exhibited different structures including cluster and lamellar shape structure, compact rod-like and network structure, and a kind of irregular geometry shape structure. In the process of coagulation-flocculation, MgSiPCs with pH 1.50-2.50 showed highly efficient coagulation performance. The removal rate of reactive yellow 2(RY2) could reach above 90% at a dosage of 50-70 mg/L and initial pH 12.00, while the removal rate of reactive blue 2 (RB2) could attain above 93% at a dosage of 50-80 mg/L and initial pH 12.00. Moreover, MgSiPCs with pH 2.00 had the highest efficiency. The results of RSM showed that the optimum combination of the MgSiPC's dosage and initial pH was 62 mg/L and 12.08 for RY2 and 78 mg/L and 12.00 for RB2, respectively. Under optimum experimental conditions, the predicted data from this model were 96% for RY2 and 100% for RB2, which was consistent with the actual experimental data. Therefore, a pH of 2.00 is considered to be the optimal acidity for preparing MgSiPCs.
一种用于从废水中去除染料的无机聚合物——硅酸镁聚合混凝剂（MgSiPC），通过共聚反应在不同pH值条件下制备而成。酸度是制备MgSiPC的关键因素。在本研究中，采用傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）和扫描电子显微镜（SEM）对最佳混凝剂的特性进行分析。此外，应用响应面法（RSM）对混凝-絮凝过程进行优化。FT-IR和XRD结果表明，pH值为1.50 - 2.50的MgSiPC主要成分基本相同。SEM图像显示，pH值为1.50 - 2.50的MgSiPC呈现出不同结构，包括簇状和层状结构、致密棒状和网络结构以及一种不规则几何形状结构。在混凝-絮凝过程中，pH值为1.50 - 2.50的MgSiPC表现出高效的混凝性能。在投加量为50 - 70 mg/L且初始pH值为12.00时，活性黄2（RY2）的去除率可达90%以上；而在投加量为50 - 80 mg/L且初始pH值为12.00时，活性蓝2（RB2）的去除率可达93%以上。此外，pH值为2.00的MgSiPC效率最高。RSM结果表明，对于RY2，MgSiPC投加量和初始pH的最佳组合分别为62 mg/L和12.08；对于RB2，分别为78 mg/L和12.00。在最佳实验条件下，该模型预测的RY2数据为96%，RB2为100%，与实际实验数据一致。因此，pH值为2.00被认为是制备MgSiPC的最佳酸度。
