In situ nanoprecipitation of cellulose acetate for removal of Janus Green dye in water

This study introduces cellulose acetate nanoparticles (CANPs) as an eco-friendly adsorbent for JG, synthesized in situ using the nanoprecipitation technique. The proposed mechanism consists of the formation of a cellulose acetate thin film upon the injection of the organic phase, followed by the rapid formation of spherical particles that entrap the dye solution. DLS analysis confirmed the successful formation of CANPs with a Z-average hydrodynamic diameter of 128.6 nm. The particle size distribution using the TEM technique was 93 ± 22 nm. The specific surface area, average pore diameter, and total pore volume of the CANPs were 1.141 m2 g−1, 28.7 nm, and 0.0082 cm3 g−1, respectively. The pHpzc of the CANPs was determined to be 6.2. The results showed that surface adsorption, upon aging the spherical particles, does not contribute significantly to the overall removal efficiency. Therefore, physical occlusion accounts for the observed high removal efficiency. Key parameters, pH, temperature, adsorbent dosage, and contact time, were optimized, with pH 8.0 at 20°C and a 15 min contact time yielding a maximum adsorption capacity of 52.64 mg g−1. Kinetic and isotherm studies suggest a pseudo-second-order model and Langmuir isotherm, indicating monolayer adsorption. Thermodynamic analysis confirms the process is exothermic and spontaneous.