College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
Chemosphere. 2023 Oct;337:139395. doi: 10.1016/j.chemosphere.2023.139395. Epub 2023 Jul 1.
Dyestuff wastewater and pharmaceutical wastewater have become typical representatives of water pollution. In this study, a novel nano-silica-biochar composite (NSBC) was synthesized based on corn straw as raw material, by a combination of ball milling, pyrolysis and KOH activation. The modified biochar with rough surface had higher specific surface area (117.67-132.82 m/g), developed pore structure (0.12-0.15 cm/g) and abundant surface functional groups (-OH, -COOH, Si-O and aromatic CC were dominated). These provided abundant active sites for the adsorption of pollutants. The adsorption capacities of NSBC for Methylene Blue (MB) and Tetracycline (TC) were both higher than that of other similar products, the maximum adsorption capacity of Langmuir were 247.22 and 86.95 mg/g, respectively. After five adsorption-desorption cycle experiments, the adsorption capacities of NSBC for both were still excellent, reaching 99.30 and 19.87 mg/g, respectively. Due to the different structure and molecular size of MB and TC, the adsorption capacities of NSBC were significantly different, especially the influence of solution pH value. The adsorption mechanisms were comprehensively discussed by FTIR and XPS of the samples before and after adsorption, and combining experimental results of BET and simultaneously, which were manifested as monolayer chemisorption, specifically surface complexation, hydrogen bonding, n-π/π-π conjugation, electrostatic interaction and pore filling.
染料废水和制药废水已成为水污染的典型代表。在本研究中，以玉米秸秆为原料，通过球磨、热解和 KOH 活化相结合，合成了一种新型纳米硅基生物炭复合材料（NSBC）。具有粗糙表面的改性生物炭具有更高的比表面积（117.67-132.82 m/g）、发达的孔结构（0.12-0.15 cm/g）和丰富的表面官能团（以-OH、-COOH、Si-O 和芳族 CC 为主）。这些为污染物的吸附提供了丰富的活性位点。NSBC 对亚甲蓝（MB）和四环素（TC）的吸附容量均高于其他类似产品，Langmuir 最大吸附容量分别为 247.22 和 86.95 mg/g。经过五次吸附-解吸循环实验，NSBC 对两者的吸附容量仍然非常优异，分别达到 99.30 和 19.87 mg/g。由于 MB 和 TC 的结构和分子尺寸不同，NSBC 的吸附容量有显著差异，特别是溶液 pH 值的影响。通过吸附前后样品的 FTIR 和 XPS 以及 BET 和同时实验结果综合讨论了吸附机理，表现为单层化学吸附、表面络合、氢键、n-π/π-π 共轭、静电相互作用和孔填充。
