Valorization of palm oil agro-waste into cellulose biosorbents for highly effective textile effluent remediation

Abstract

Over the past few decades, enormous interest has been manifested in utilizing biomass or agricultural wastes as a renewable resource for energy and advanced material production. Despite being the utmost abundant polymer on earth, nanocellulose has drawn tremendous attention due to its intrinsic reliability and sustainability. In this study, nanocrystalline cellulose (NCC) was isolated from oil palm biomass waste i.e. oil palm empty fruit bunch (EFB) via a multistep process to testify its high capacity as a biosorbent for textile effluent contaminant remediation. Fourier transform infrared spectroscopy (FTIR) suggested that lignin, hemicellulose and other impurities had been effectively removed at different stages of preparation which was generally in agreement with ASTM chemical composition analysis. Thermogravimetric analysis with derivative thermograms (TGA-DTG) observed the extracted NCC to have the lowest weight loss throughout water evaporation region (25 °C - 100 °C), cellulose thermal degradation region (150 °C - 380 °C) and carbonic residue degradation (up to 600 °C) owing to its compact crystalline structure as evidenced from X-ray diffraction (XRD) analysis. Batch adsorption were conducted to study effect of contact time (up to 200 min), adsorbent dosage (0.005–0.05 g), pH (2–10), agitation (50–250 rpm) and adsorbate concentration (50–300 mg/L) at 30 ± 2 °C. Field emission scanning electron microscope (FESEM) observed a flower-like structure of methylene blue (MB) coating upon adsorption, following a type II adsorption isotherm which suggest an adsorption occurred on mesoporous structure. The kinetic data agreed well with pseudo-second-order model which implied the current study a chemisorption process. As adsorption capacity was highly dependent on adsorbate concentration and adsorbent dosage, 50.91 mg/g was recorded for MB solution (50 mg/L) at adsorbent dosage as low as 0.066 mg/ml; a very encouraging outcome in the recent years of cellulosic research suggesting NCC a highly promising candidate for uprising functional cellulosic soft material fabrication.