The objective of this project was to develop a new bioproduct that will utilize agricultural waste and modify the product to increase its present adsorption capacity. After the hydrothermal carbonization of corn silk, a novel hydrochar was generated and treated using sulfuric acid to boost its adsorption capacity. FT-IR, SEM–EDX, TGA, and BET surface analysis studies were used to analyze the structure of the produced biosorbents. According to the EDX analysis results, there are C, H, and N elements in the hydrochar structure, and the treated hydrochar contains S in addition to these elements. While the presence of several functional groups was indicated by FT-IR data, post-adsorption EDX analysis proved that Cr ions were adhering to hydrochar. The proper parameters for the adsorption processes for both biosorbents were established. By analyzing the outcomes of kinetics tests at various concentrations and isotherm experiments, the adsorption procedure was identified. The pseudo-second-order kinetic model was shown to be consistent with the kinetic pathways of adsorptions. Although the results of the isotherm experiments also suited the Langmuir isotherm, the Freundlich isotherm had higher R² values and was more consistent with the results. The outcomes demonstrated that sulfuric acid-modified hydrochar offered greater Cr(VI) adsorption capacity. q_m values defining the maximum adsorption capacities of HC and THC at a temperature of 333 K were estimated to be 263.16 and 294.12 mg g⁻¹, in that order. Based on the q_m values, the adsorption capabilities of HC and THC were compared with those of a few other adsorbents. THC (29.11 m² g⁻¹) had a 29% larger surface area than HC (22.57 m² g⁻¹), according to the surface area of BET test results.

中文翻译：

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水热炭化玉米丝生产水炭及其改进以更有效地去除Cr(VI)

该项目的目标是开发一种新的生物产品，该生物产品将利用农业废物并改进该产品以提高其现有的吸附能力。玉米丝水热碳化后，产生了一种新型水炭，并用硫酸处理以提高其吸附能力。FT-IR、SEM-EDX、TGA 和 BET 表面分析研究用于分析所生产的生物吸附剂的结构。根据EDX分析结果，水炭结构中存在C、H、N元素，处理后的水炭除这些元素外还含有S。虽然 FT-IR 数据表明存在多个官能团，但吸附后 EDX 分析证明 Cr 离子粘附在水炭上。建立了两种生物吸附剂吸附过程的适当参数。通过分析不同浓度的动力学测试结果和等温线实验，确定了吸附过程。准二级动力学模型与吸附动力学路径一致。虽然等温线实验的结果也符合Langmuir等温线，但Freundlich等温线的R ²值更高，与结果更一致。结果表明，硫酸改性水炭具有更大的 Cr(VI) 吸附能力。定义333 K温度下HC和THC最大吸附容量的q _m^{值估计依次为263.16和294.12 mg g -1}。根据q _m值，将 HC 和 THC 的吸附能力与其他几种吸附剂进行比较。根据BET测试结果的表面积，THC（29.11 m ²  g ^{-1 ）的表面积比HC（22.57 m 2}  g ^-1 ）大29% 。