Synthesis of hybrid layered double hydroxides (HLDH) and application as adsorbent for removal of direct sky-blue dye

AbstractHybrid Layered Double Hydroxides (HLDH) are promising adsorption materials for water treatment due to their excellent anion exchange capacities, abundance of active sites, and eco-friendliness. HLDH was synthesized utilizing the co-precipitation technique in this work to demonstrate its applicability for the removal of direct sky-blue dye via an adsorption procedure. The effects of pH, dose, contact time, initial dye concentration, and temperature on the direct sky-blue dye adsorption efficiency were thoroughly investigated. The adsorbents were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), energy dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET). Under the best conditions, the maximum adsorption capacity has been achieved for Mg–Cr–Cl (42.95 mg/g) > Zn–Al–CO3 (39.76 mg/g) > Mg–Fe–Cl (38.08 mg/g). The adsorption of dyes on Mg–Cr–Cl, Zn–Al–CO3, and Mg–Fe–Cl followed a pseudo-second-order kinetic model and exhibited Langmuir-type monolayer adsorption. The influence of temperature was studied to determine the thermodynamic parameters. The estimated results showed spontaneous and exothermic adsorption processes. Electrolyte enhances the adsorption capacity to some extent, while surfactants block the sites, thus reducing the adsorption capacity. The maximum desorption of dye was influenced by the sodium hydroxide solution. The research described here might be utilized to create novel adsorbents with improved adsorption capacities for preserving the aquatic environment.Keywords: Adsorption–desorptiondirect sky-blue dyeMg–Cr–Cl HLDHMg–Fe–Clthermodynamic parametersZn–Al–CO3 AcknowledgmentThe authors would like to extend their sincere appreciation to the acknowledgment; research supporting project (RSP-2023/95, King Saud University, Riyadh, Saudi Arabia).Author contribution statementAhsan Maqsood: Methodology, Writing- original draft, Ruba Munir: Methodology, Formal analysis, acquisition of data, Saima Noreen: Supervision, Conceptualization, Formal analysis, Resources, Gadah Albasher: Conceptualization, Resources, Writing-review& editing, Amna Muneer: Statistical analysis, Writing-review & editing, Murtaza Sayed: execution, Writing-review& editing, Muhammad Yaseen: interpretation, Writing-review& editing, Fazila Younas: Conceptualization, interpretation, Raziya Nadeem: Conceptualization, interpretation, Muhammad Zahid: execution, Writing-review& editing, Nazish Jahan: execution, Writing-review& editing.Consent for publicationAll authors have read and approved this manuscript.Consent to participateNot applicable.Data availabilityData will be made available on reasonable request.Disclosure statementThe authors declare no competing interests.Ethical approvalResearch does not involve Human Participants or/and Animals.