Amiri Mohammad Javad, Raayatpisheh Maryam, Radi Mohsen, Amiri Sedigheh
Department of Water Engineering, Faculty of Agriculture, Fasa University, Fasa, 74616-86131, Iran.
Department of Food Science and Technology, Yasooj Branch, Islamic Azad University, Yasooj, Iran.
Sci Rep. 2023 Oct 12;13(1):17263. doi: 10.1038/s41598-023-44613-6.
In the present study, four biopolymer-based materials consisting of native corn starch (CS), phosphate corn starch (PS), starch nanocrystals (SNCs), and phosphate corn starch nanocrystals (PSNCs) were synthesized and used for methylene blue (MB) removal as a function of various parameters, including initial MB concentration (C0, 10-500 mg L), adsorbent dosage (Cs, 0.02-0.15 g), contact time (t, 5-15 min), solution pH (2-11), and temperature (25-45 °C). The removal percentage of MB increased dramatically upon increasing the biopolymer dosage, temperature, and pH; while it decreased upon increasing the initial MB concentration. The adsorption behavior of biopolymer-based materials towards MB was found to be accurately described by the pseudo-second-order kinetic and Langmuir isotherm models. According to the Langmuir model, the maximum adsorption capacities of the adsorbents were ordered as follows: PSNCs (88.53 mg g) > SNCs (79.55 mg g) > PS (73.17 mg g) > CS (63.02 mg g). PSNCs was able to remove 96.8% and 76.5% of 20 mg L MB in greywater and petrochemical wastewater, respectively, at an optimum pH of 9 and retained 86.42% of its usability even after five adsorption-desorption cycles. The analysis of the surface charge of the adsorbents before and after MB adsorption, combined with the FTIR spectrum of MB-saturated biopolymer-based materials, provided evidence that electrostatic interactions was the primary mechanism involved in the adsorption of MB. Meanwhile, hydrogen bonding and π-π interactions were found to have a minor contribution to the adsorption process. Based on the results, it can be inferred that PSNCs has promising potential as an adsorbent for the treatment of MB-containing wastewater, owing to its exceptional properties, which include high adsorption capacity, low cost, and applicability for multiple reuses.
在本研究中，合成了四种基于生物聚合物的材料，分别由天然玉米淀粉（CS）、磷酸玉米淀粉（PS）、淀粉纳米晶体（SNCs）和磷酸玉米淀粉纳米晶体（PSNCs）组成，并用于去除亚甲基蓝（MB），研究了包括初始MB浓度（C0，10 - 500 mg/L）、吸附剂用量（Cs，0.02 - 0.15 g）、接触时间（t，5 - 15 min）、溶液pH值（2 - 11）和温度（25 - 45°C）等各种参数对MB去除的影响。随着生物聚合物用量、温度和pH值的增加，MB的去除率显著提高；而随着初始MB浓度的增加，去除率降低。基于生物聚合物的材料对MB的吸附行为可用准二级动力学和朗缪尔等温线模型准确描述。根据朗缪尔模型，吸附剂的最大吸附容量顺序如下：PSNCs（88.53 mg/g）＞SNCs（79.55 mg/g）＞PS（73.17 mg/g）＞CS（63.02 mg/g）。在最佳pH值为9时，PSNCs能够分别去除灰水和石化废水中20 mg/L MB的96.8%和76.5%，并且即使经过五次吸附 - 解吸循环后仍保留其86.42%的可用性。对MB吸附前后吸附剂表面电荷的分析，结合MB饱和的基于生物聚合物的材料的FTIR光谱，证明静电相互作用是MB吸附的主要机制。同时，发现氢键和π - π相互作用对吸附过程的贡献较小。基于这些结果，可以推断PSNCs作为含MB废水处理的吸附剂具有广阔的应用前景，这归因于其优异的性能，包括高吸附容量、低成本和多次重复使用的适用性。
