Assessment of sulfamethoxazole adsorption capacity on Pirangi clay from the State of Sergipe, Brazil, modified by heating and addition of organic cation

Abstract

Sulfamethoxazole (SMX) is a widely-used antibiotic in human and veterinary medicine for treating diseases and infections and is often detected in the surface water ecosystem. Thus, this study evaluated the capacity of removing SMX from aqueous systems using Pirangi clay (PIR) from the state of Sergipe (Brazil). Pirangi clay samples were treated at 100, 400 and 600 °C and modified with hexadecyltrimethylammonium (HDTMA) cationic surfactant. The modification process used was based on the layered organization of the mineral clay, allowing the intercalation of cationic surfactant, giving a hydrophobic character to the clay. The Pirangi clay treated at 100 °C and modified with HDTMA (org-PIR-100) showed adsorption capacity of 27.3 mg.g-1 with 90% removal of the SMX in 100 min and pH 6, following the pseudo-second-order model and Langmuir isotherm. Different characterization methods were employed to characterize the clays, such as XRF, FTIR, XRD, thermogravimetric analyzes (TG/DTG) and BET method, confirming that the surfactant molecules were incorporated on the clay surface and that org-PIR-100 showed potential for use in water treatment plant filters.

The synergistic action of cyclodextrin-based adsorbent and advanced oxidation processes for sulfamethoxazole removal from water

“…The SMX has two pK a values: pK a1 = 1.6, corresponding to the aniline N's protonation, and pK a2 = 5.7, relative to the sulfonamide deprotonation. The maximum adsorption efficiency, 84 and 87%, respectively, were obtained at pH 2.0 and 4.5, which are between pK a1 and pK a2 (Rezende et al 2019) where SMX exists mostly as SMX 0 . This result suggests that weak hydrophobic interactions are more important in the adsorption process onto β-EPI, than electrostatic ones, contrary to that reported in the literature in the case of SMX adsorption on activated carbons (Prasannamedha and Kumar 2020).…”

Adsorption of Estradiol by Natural Clays and Daphnia magna as Biological Filter in an Aqueous Mixture with Emerging Contaminants

“…Nicotine, sulfamethoxazole, and triclosan were not quantified in this study. Other studies show that these compounds are poorly or not removed with natural clays and a pre-treatment of clay is necessary to achieve the adsorption [54][55][56]. Considering the soil adsorption coefficient (Koc) which measures the amount of chemical substance adsorbed onto soil per amount of water, estradiol is prone to be adsorbed in clays.…”

Mathematical modeling of the equilibrium and kinetics of sulfamethoxazole adsorption from aqueous solution

“…Com a posse dos dados experimentais de adsorção de sulfametoxazol em argila pirangi organofílica, fornecidos por Rezende (2019a) eRezende et al (2019b) foram construídas as Tabelas 1, 2 e 3 que estão apresentadas abaixo.Tabela 1 -Condições operacionais do experimento. pelos autores com base em Rezende (2019a) eRezende et al (2019b) …”