Data from: Sustainable wastewater decontamination of chlortetracycline using kaolin-alginates beads: Practical applications and adsorption mechanisms

This study systematically evaluates the adsorption performance of kaolin
(KN), kaolin-alginate beads (KN@Alg), and activated carbon (AC) for
chlortetracycline (CTC) removal from water. Comprehensive characterization
using FT-IR, SEM-EDX, XRD, and XPS revealed that incorporating alginate
into KN significantly enhanced its adsorption capacity by increasing
binding sites. KN@Alg exhibited a superior adsorption capacity (68.74
mg/g) compared to KN (42.76 mg/g), though slightly lower than AC (102.96
mg/g). In terms of removal efficiency, KN@Alg (68.44%) and AC (79.45%)
outperformed KN (55.04%). Kinetic studies indicated that CTC adsorption on
KN and KN@Alg followed both pseudo-first-order and pseudo-second-order
models, suggesting combined physisorption and chemisorption mechanisms,
while AC adsorption was dominated by physisorption. Isotherm analysis
showed that KN@Alg exhibited greater surface heterogeneity, with
adsorption well-described by the Freundlich and Langmuir models, whereas
KN and AC followed the Langmuir model. Thermodynamic analysis confirmed
that CTC adsorption on KN@Alg was exothermic and spontaneous, with optimal
performance at 298 K, while KN displayed limited capacity across
temperatures. KN@Alg addressed key limitations of KN (recycling
difficulties, particle aggregation) and pure alginate beads (instability,
low reuse rates), while enhancing adsorption performance. Regeneration
studies over four cycles demonstrated KN@Alg’s superior reusability
compared to AC and KN. Dynamic studies using solid-phase extraction (SPE)
cartridges and continuous bead columns achieved exceptional CTC removal
rates of 93.8% and 93.7%, respectively, in river water samples containing
5 mg/L CTC, showcasing KN@Alg’s practical applicability. XPS analysis
revealed multiple adsorption mechanisms, including n-π interactions,
hydrogen bonding, electrostatic, cation exchange, and cation-bridging
interactions involving calcium-alginate groups and kaolin’s Si/Al
components. These findings highlight KN@Alg as a cost-effective,
sustainable alternative to AC for CTC removal in water treatment.