Eco-friendly approach for effective removal for Congo red dye from wastewater using reusable Zn-Al layered double hydroxide anchored on multiwalled carbon nanotubes supported sodium dodecyl sulfonate composites

Abstract

Herein, high-activityand petal-like Zn-Al layered double hydroxide/multiwalled carbon nanotubes supported sodium dodecyl sulfonate (Zn-Al LDH/SDS/MWCNTs) composites were successfully synthesized as novel, eco-friendly and effective adsorbents. The particularly physical and chemical properties of Zn-Al LDH/SDS/MWCNTs composites were characterized in detail. Besides, the adsorption performance and interaction mechanism of Congo red onto Zn-Al LDH/SDS/MWCNTs were also investigated under various experiment conditions. The initial pH values and adsorbent concentration played significant part in adsorption performance of Congo red dye. The adsorption kinetics and temperature-dependent isotherms of Congo red onto Zn-Al LDH/SDS/MWCNTs were respectively consistent with pseudo second-order model and Langmuir model. The maximum adsorption capacity of Congo red was greatly achieved to 1.42 × 10−3 mol/g adopting Langmuir model, which was much better than those previously reported other composites to date. The experimental results illustrated that the adsorption performance of Congo red onto Zn-Al LDH/SDS/MWCNTs composites was primarily contributed to surface complexation, ion change, π-π interaction, electrostatic interaction together with hydrogen bond to some extent. The experimental results demonstrated that the as-synthesized Zn-Al LDH/SDS/MWCNTs composites are remarkable adsorbents for the wastewater treatment systems. Our study initials a new foresight for understanding the interaction mechanism and preparing highly efficient and eco-friendly adsorbents with excellent adsorption performance for the elimination of organic contaminants.