Parabens Adsorption onto Activated Carbon: Relation with Chemical and Structural Properties

Abstract

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 CaCl2 (GC2), MgCl2 (GM2) and Cu(NO3)2 (GCu2) at 2% wt/v and carbonized in CO2 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 m2 × g−1, while the highest values correspond to the activated carbon GCu2, with a surface area of 896 m2 × g−1 and the highest content of surface acid sites (0.42 mmol × g−1), 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−1 for MePB adsorption and 1.24 and 52.38 J × g−1 for EtPB adsorption showing that the process is endothermic.

Impregnation of Modified Magnetic Nanoparticles on Low-Cost Agro-Waste-Derived Biochar for Enhanced Removal of Pharmaceutically Active Compounds: Performance Evaluation and Optimization Using Response Surface Methodology

“…These results are in agreement with the kinetic data obtained for ASA and CBZ removal. As the linear segments in neither graph plotted between q t and t 1/2 for the intraparticle diffusion model pass through the origin, this indicates that intraparticle diffusion is not the only rate-controlling step; there are additional kinetic processes, such as boundary layer effects, which regulate the adsorption rate [77,83]. Table 6 displays the kinetic model parameters discussed above.…”

Preparation of Biochar with Developed Mesoporous Structure from Poplar Leaf Activated by KHCO3 and Its Efficient Adsorption of Oxytetracycline Hydrochloride

“…Recently, biochar has been widely used to remove antibiotics from the environment due to its porous structure and low cost [ 26 , 27 , 28 ]. However, biochar obtained from the direct pyrolysis of biomass usually has a low specific surface area, undeveloped pore structure, and few adsorption sites, resulting in its poor adsorption performance [ 29 , 30 ]. In order to optimize the adsorption performance of biochar, activating agents are usually added during the synthesizing process.…”

Preparation of COPs Mixed Matrix Membrane for Sensitive Determination of Six Sulfonamides in Human Urine

“…Adsorbents with excellent performance can ensure effective enrichment and purification of samples. Various studies have explored adsorbents, such as carbon nanotubes [23], activated carbon [24], metallic organic frameworks [25], covalent organic polymers (COPs) [26], and others.…”