Departamento de Química, Universidad Nacional de Colombia, 111321 Bogotá, Colombia.
Departamento de Química, Universidad de los Andes, 111711 Bogotá, Colombia.
Molecules. 2019 Nov 26;24(23):4313. doi: 10.3390/molecules24234313.
Parabens (alkyl-p-hidroxybenzoates) are antimicrobial preservatives used in personal care products, classified as an endocrine disruptor, so they are considered emerging contaminants. A raw version of activated carbons obtained from African palm shell (Elaeis guineensis) modified chemically by impregnation with salts of CaCl (GC2), MgCl (GM2) and Cu(NO) (GCu2) at 2% / and carbonized in CO atmosphere at 1173 K was prepared. The process of adsorption of methyl (MePB) and ethylparaben (EtPB) from aqueous solution on the activated carbons at 18 °C was studied and related to the interactions between the adsorbate and the adsorbent, which can be quantified through the determination of immersion enthalpies in aqueous solutions of corresponding paraben, showing the lowest-value carbon GM2, which has a surface area of 608 m × g, while the highest values correspond to the activated carbon GCu2, with a surface area of 896 m × g and the highest content of surface acid sites (0.42 mmol × g), such as lactonic and phenolic compounds, which indicates that the adsorbate-adsorbent interactions are favored by the presence of these, with interaction enthalpies that vary between 5.72 and 51.95 J × g for MePB adsorption and 1.24 and 52.38 J × g for EtPB adsorption showing that the process is endothermic.
对羟基苯甲酸酯（烷基-对羟基苯甲酸酯）是一种用于个人护理产品的抗菌防腐剂，被归类为内分泌干扰物，因此被认为是新兴污染物。从非洲棕榈壳（油棕）中获得的未经处理的活性炭，通过用 CaCl（GC2）、MgCl（GM2）和 Cu（NO3）（GCu2）的盐浸渍并在 CO 气氛中于 1173 K 碳化来进行化学改性。在 18°C 下，研究了从水溶液中吸附甲基（MePB）和乙基对羟基苯甲酸酯（EtPB）到活性炭上的过程，并与吸附物和吸附剂之间的相互作用有关，这可以通过测定相应对羟基苯甲酸酯在水溶液中的浸出焓来定量，结果表明具有最低值的碳 GM2 具有 608 m²/g 的表面积，而具有最高值的则对应于活性炭 GCu2，其表面积为 896 m²/g，且表面酸性位（如内酯和酚类化合物）的含量最高（0.42 mmol×g），这表明吸附物-吸附剂相互作用受到这些化合物的存在的促进，其相互作用焓值在 5.72 和 51.95 J×g 之间变化，用于 MePB 吸附，在 1.24 和 52.38 J×g 之间变化，用于 EtPB 吸附，表明该过程是吸热的。
