Methylparaben (MePB) is a type of emerging contaminant
[1]
, commonly present in wastewater and surface water, widely used as preservatives in personal care products. The risk associated with the presence of this pollutant in the environment is due to their classification as an endocrine disruptor
[2]
. Two activated carbons obtained from African palm shell (Elaeis Guineensis) modified chemically by impregnation with CaCl
2
(GC1) and MgCl
2
(GM1) at 1% wt/v and carbonized in CO
2
atmosphere at 1173 K, were prepared. The process of adsorption of methylparaben from aqueous solution to activated carbon is due to the interactions between the adsorbate and the adsorbent, which can be quantified through the determination of immersion enthalpies in aqueous solutions of MePB, finding values of - 22.45 and −45.23 J g
−1
for the immersion in the solution of 100 mg L
−1
, -3.31 and −44.02 J g
−1
for the immersion in the solution of 200 mg L
−1
and -21.31 and −54.51 J g
−1
, showing the highest values carbon GC1. To evaluate the efficiency of MePB adsorption on the obtained solids, Langmuir and Freundlich adsorption models were determined in order to relate the quantities adsorbed with the immersion enthalpies and know the intensity of the energy interactions between the MePB and the activated carbons.
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.
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