College of Agricultural Engineering, Campinas State University, Ave. Cândido Rondon, 501, Cidade Universitária, Campinas 13.083-875, São Paulo, Brazil; Department of Agricultural Engineering, Federal University of Viçosa, Ave. P. H. Rolfs s/n, Viçosa 36.570-900, Minas Gerais, Brazil.
Department of Chemistry, University of the Minas Gerais State, Ave. Olegário Maciel, 1427, Ubá 36.500-000, Minas Gerais, Brazil.
Sci Total Environ. 2020 Nov 20;744:140864. doi: 10.1016/j.scitotenv.2020.140864. Epub 2020 Jul 15.
A feasible, novel, and natural coagulant extracted from G. ulmifolia stem bark was characterized and used in experiments of coagulation/dissolved air flotation (C/DAF) to treat synthetic dairy wastewater (SDW). The performance of G. ulmifolia to remove turbidity, chemical oxygen demand (COD), and UV was evaluated by using response surface methodology (Doehlert matrix). G. ulmifolia dosage and pH were evaluated and optimized in the C/DAF process and its characterization was performed by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and also zeta potential. Results showed that G. ulmifolia stem bark is composed of large quantities of condensed tannins represented by the groups C=C-C and CO of pyran (flavonoid C-rings), which serve as bridges during coagulation. Moreover, the presence of porous cavities in surface of G. ulmifolia, shown by SEM, indicated capacity for adsorption. G. ulmifolia dosage and pH were significant (p ≤ 0.05) for pollutant removal from the SDW. Jar test results revealed that 95.8% of turbidity, 76.0% of COD, 81.2% of BOD, and 85.6% of UV were removed from SDW by using G. ulmifolia stem bark at a dose of 775.8 mg L and pH 5.00. Finally, our results showed promising use of G. ulmifolia as a coagulating agent due to its novelty, efficiency, low-cost, and eco-friendly properties as an alternative for the treatment of dairy wastewaters.
从榉木叶中提取的一种可行的、新颖的、天然的混凝剂，具有良好的混凝性能，可用于混凝/溶气浮选（C/DAF）实验，以处理合成乳制品废水（SDW）。采用响应面法（Doehlert 矩阵）评价了 G. ulmifolia 对去除浊度、化学需氧量（COD）和紫外光（UV）的性能。通过傅里叶变换红外（FTIR）光谱、扫描电子显微镜（SEM）和zeta 电位对 G. ulmifolia 的用量和 pH 值进行了评价和优化，并对其进行了表征。结果表明，G. ulmifolia 树皮中含有大量的缩合单宁，由 C=C-C 和吡喃（类黄酮 C-环）的 CO 基团表示，这些基团在混凝过程中充当桥接物。此外，SEM 显示 G. ulmifolia 表面存在多孔腔，表明其具有吸附能力。G. ulmifolia 的用量和 pH 值对 SDW 中污染物的去除具有显著影响（p≤0.05）。搅拌试验结果表明，使用 775.8mg/L 的 G. ulmifolia 树皮和 pH 值为 5.00 时，SDW 中的浊度、COD、BOD 和 UV 的去除率分别达到 95.8%、76.0%、81.2%和 85.6%。最后，由于其新颖性、效率、低成本和环保特性，作为处理乳制品废水的替代物，G. ulmifolia 具有广阔的应用前景。
