Physical Organic Chemistry Group, Department of Chemistry, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Campus Universitário Morro do Cruzeiro, s/n°, Bauxita, 35400-000, Ouro Preto, Minas Gerais, Brazil.
Environ Sci Pollut Res Int. 2022 Nov;29(53):79954-79976. doi: 10.1007/s11356-022-18654-9. Epub 2022 Feb 21.
This study reports the use of multivariate tools to optimize the synthesis of a new agricultural-based biosorbent derived from sugarcane bagasse (SB) for the removal of Cd(II) and Pb(II) from aqueous solutions, as well as to optimize the process of desorption of these ions from the spent biosorbent using an acidic solution. The effects of the reaction parameters temperature (T), time (t), and the ratio of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCAD) to raw SB (w w) on the chemical modification of raw SB with BTCAD and on the equilibrium adsorption capacity (q) for Cd(II) and Pb(II) were investigated by application of a 2 Doehlert experimental design (DED), followed by optimization using a statistical desirability tool to produce the best adsorbent in terms of performance and cost. The best reaction condition was w w of 4.0 g g, t of 1 h, and T of 70 ºC. The optimal synthesis condition resulted in a modified sugarcane bagasse (MSB) that provided q values for Cd(II) and Pb(II) of 0.50 and 0.61 mmol g, respectively, obtained under the following conditions: 0.311 mmol Cd(II) L, 0.632 mmol Pb(II) L, pH 5.0, 4 h, 0.2 g L MSB, 130 rpm, and 25 °C. The desorption of Cd(II) and Pb(II) from MSB was investigated by a 2 DED, with optimization using the desirability tool to obtain the best desorption condition in terms of HNO solution concentration ([Formula: see text]) and t. The desorption efficiencies for Cd(II) and Pb(II) were 90 ± 4% and 88 ± 3%, respectively, obtained using 0.7 mol L HNO, t of 42 min, and 1.0 g L MSB-M(II) (M = Pb or Cd). Infrared spectroscopy was used to investigate the natures of the interactions involved in the adsorption of Cd(II) and Pb(II) on MSB, as well as possible changes in the chemical structure of MSB after desorption. The synthesis of MSB can be performed under mild reaction conditions (t = 1 h, T = 70 ºC), and the solvents used can be recovered by distillation. BTCA is commercially available at moderate cost and can alternatively be obtained employing microbial succinic acid, metal-free catalysis, and modest use of petrochemical feedstocks. Furthermore, MSB can be reused, which could contribute to increasing the economic feasibility of water and wastewater treatment processes.
本研究报告了使用多元工具优化从甘蔗渣（SB）中衍生的新型农业生物吸附剂的合成，以去除水溶液中的 Cd(II)和 Pb(II)，以及优化使用酸性溶液从废生物吸附剂中解吸这些离子的过程。通过应用 2 Doehlert 实验设计 (DED) 研究了反应参数温度 (T)、时间 (t) 和 1,2,3,4-丁烷四羧酸二酐 (BTCAD) 与原始 SB 的质量比 (w w ) 对原始 SB 进行化学修饰以及对 Cd(II)和 Pb(II)的平衡吸附容量 (q) 的影响，然后使用统计可接受性工具进行优化，以生产在性能和成本方面表现最佳的吸附剂。最佳反应条件为 w w 为 4.0 g g ，t 为 1 h ，T 为 70 ºC。最佳合成条件得到改性甘蔗渣 (MSB)，在以下条件下 Cd(II)和 Pb(II)的 q 值分别为 0.50 和 0.61 mmol g ：0.311 mmol Cd(II) L ，0.632 mmol Pb(II) L ，pH 5.0 ，4 h ，0.2 g L MSB ，130 rpm ，25 ºC。通过 2 DED 研究了 Cd(II)和 Pb(II)从 MSB 的解吸，使用可接受性工具优化以获得最佳解吸条件，考虑到 HNO 溶液浓度 ([Formula: see text]) 和 t 。Cd(II)和 Pb(II)的解吸效率分别为 90±4%和 88±3%，使用 0.7 mol L HNO ，t 为 42 min ，1.0 g L MSB-M(II)（M=Pb 或 Cd ）。红外光谱用于研究 Cd(II)和 Pb(II)在 MSB 上吸附的相互作用性质，以及 MSB 解吸后化学结构可能发生的变化。MSB 的合成可以在温和的反应条件下（t=1 h ，T=70 ºC ）进行，并且可以通过蒸馏回收使用的溶剂。BTCA 商业上可获得且价格适中，也可以采用微生物丁二酸、无金属催化和适度使用石化原料的方法获得。此外，MSB 可以重复使用，这可能有助于提高水和废水处理工艺的经济可行性。
