Untapped conversion of plastic waste char into carbon-metal LDOs for the adsorption of Congo red

A low-cost novel carbon-metal double layered oxides (C/MnCuAl-LDOs) nano-adsorbent was synthesized by co-precipitation, for the adsorption of Congo red (CR), using modified carbon derived from pyrolysis of polystyrene (PS) plastic waste. The synthesized C/MnCuAl-LDOs has a crystalline structure with a high surface area of 60.43 m²/g and pore size of 99.85 Å. Adsorption of CR using all prepared adsorbents from aqueous solution under equilibrium and kinetic conditions were evaluated against different values of the pH (4–10), initial CR concentrations (25–250 mg/g), contact time (0–310 min) and temperature (30–50 °C). The obtained results revealed that C/MnCuAl-LDOs showed maximum adsorption capacity for CR among all the used adsorbents. The optimum equilibrium time was 180 min, whereas acidic medium (pH 4.5) favored the maximum adsorption of CR up to 317.2 mg/g on C/MnCuAl-LDOs. The adsorption kinetics followed the pseudo-second-order model, whereas Freundlich adsorption isotherm fitted best to obtained data in comparison to Langmuir adsorption isotherm. The results suggested that C/MnCuAl-LDOs is an efficient material for the removal of organic pollutants from the wastewater.