Abstract

Activated carbons are prepared by conventional two-stage carbonization–activation processing and complex processing of spent coffee grounds. The latter method includes preliminary solvent extraction of organic compounds. The samples prepared by conventional and complex processing methods have a high BET (Brunauer–Emmett–Teller) surface area (S_BET = 864 and 1089 m²/g, respectively), specific surface area of mesopores (400 and 464 m²/g), and total pore volume V_Σ (0.68 and 0.87 mL/g). It is shown that the complex processing produces activated carbons with a specific surface area 27% higher, compared to the conventional method. We propose that this sorption material can be used in purification of pharmaceutical production effluents. The capacity of the carbons to adsorb phenolic acids, in particular, salicylic and sulfosalicylic acids, which represent pharmaceutical microimpurities, is studied. The equilibrium concentrations of salicylic and sulfosalicylic acids are determined spectrophotometrically at λ = 296 and 294 nm, respectively, using a UV-2450 instrument (Shimadzu, Japan). The carbon produced by complex processing exhibits the most effective sorption properties (18 mg/g). The carbon prepared by conventional method displays intermediate characteristics (13.3 mg/g), and a reference Natural Brand adsorbent derived from lignocellulose material has the lowest characteristics (11.4 mg/g). The same pattern is observed for adsorption of sulfosalicylic acid, with the saturation adsorption being lower for sulfosalicylic than salicylic acid. We can state that substances with good solubility in water exhibit poorer physical adsorption than those with limited solubility. Processing the experimental data within the Langmuir and Freundlich adsorption models suggests that adsorption of the phenolic acids on the highly porous sorbents follows the Langmuir model, i.e., adsorption occurs at active sites where a dynamic equilibrium is established between adsorption and desorption processes.

中文翻译：

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废咖啡渣复合加工制得的碳粉对酚酸的吸附

摘要

活性炭是通过常规的两阶段碳化-活化处理和废咖啡渣的复杂处理来制备的。后一种方法包括有机化合物的初步溶剂萃取。通过常规和复杂的加工方法制备的样品具有高的BET（Brunauer-Emmett-Teller）表面积（S _BET分别为864和1089 m ² / g），中孔的比表面积（400和464 m ² / g） ），和总孔体积V _Σ（0.68和0.87 mL / g）。结果表明，与常规方法相比，复杂的过程可生产出比表面积高27％的活性炭。我们建议这种吸附材料可用于制药生产废水的纯化。研究了碳吸附代表药物微杂质的酚酸，特别是水杨酸和磺基水杨酸的能力。水杨酸和磺基水杨酸的平衡浓度分别使用UV-2450仪器（日本岛津制作所）以分光光度法在λ= 296和294 nm处测定。通过复杂工艺生产的碳表现出最有效的吸附性能（18 mg / g）。通过常规方法制得的碳显示出中间特性（13.3 mg / g），木质纤维素材料衍生的天然牌号吸附剂的特性最低（11.4 mg / g）。对于磺基水杨酸的吸附观察到相同的模式，其中磺基水杨酸的饱和吸附低于水杨酸。我们可以说，在水中具有良好溶解度的物质比具有有限溶解度的物质表现出较差的物理吸附。在Langmuir和Freundlich吸附模型中处理实验数据表明，高度多孔吸附剂上酚酸的吸附遵循Langmuir模型，即吸附发生在活性部位，在吸附和解吸过程之间建立了动态​​平衡。对于磺基水杨酸的吸附观察到相同的模式，其中磺基水杨酸的饱和吸附低于水杨酸。我们可以说，在水中具有良好溶解度的物质比具有有限溶解度的物质表现出较差的物理吸附。在Langmuir和Freundlich吸附模型中处理实验数据表明，高度多孔吸附剂上酚酸的吸附遵循Langmuir模型，即吸附发生在活性部位，在吸附和解吸过程之间建立了动态​​平衡。对于磺基水杨酸的吸附观察到相同的模式，其中磺基水杨酸的饱和吸附低于水杨酸。我们可以说，在水中具有良好溶解度的物质比具有有限溶解度的物质表现出较差的物理吸附。在Langmuir和Freundlich吸附模型中处理实验数据表明，高度多孔吸附剂上酚酸的吸附遵循Langmuir模型，即吸附发生在活性部位，在吸附和解吸过程之间建立了动态​​平衡。