Cellulose/castor oil‐based polyurethane film composite for aqueous Cd and Pb adsorption: Evaluation using laser‐induced breakdown spectroscopy

Castor oil‐based polyurethane has been researched for its utility in heavy metal adsorption. To improve the adsorptive performance, the polymer can be incorporated with cellulose—a renewable and widely available biopolymer. The aim of this research was to synthesize a film composite prepared from castor oil‐based polyurethane and cellulose for adsorptive removal of aqueous Cd and Pb. One‐shoot synthesis method was employed by mixing cellulose filler with castor oil and toluene diisocyanate (TDI). Characterization was carried out by FT‐IR, SEM, TGA, DSC, and contact angle analyses. Batch adsorption was carried out for the Cd and Pb with variations in contact time and initial pH, before analyzed for the adsorptive performance using 1064 nm Nd:YAG laser spectroscopy. The resulted adsorbents had improved thermal stability, and lower hydrophobicity. Adsorption of Pb and Cd increased 2 and 35 times after the addition of 0.1 g cellulose, respectively. Batch adsorption test revealed that the optimum conditions are 120‐min contact time and pH of 9 and 7 (for Cd and Pb, respectively). In conclusion, incorporation of cellulose could modify the characteristics of castor oil‐based polyurethane film and improve the adsorption of Cd and Pb.