Optimization of adsorption conditions for removal of total organic carbon from drinking water using polypropylene and titanium dioxide nano-composite by response surface methodology

摘要

Identification of organic carbon in drinking water can indicate the presence of hazardous pollutants that are capable of threatening human health and aquatics. This study was conducted to optimize adsorption of total organic carbon (TOC) using polypropylene/titanium dioxide nano-composite from drinking water by response surface methodology (RSM). Activation of polypropylene (PP) fibers was achieved via wet heating. To synthesize the nano-composite, activated PP fibers were coated with nano-TiO2 in sonication chamber. The morphology of the fractured surfaces of impact specimens was examined by field-emission scanning electron microscopy (FE-SEM). After FTIR spectroscopy and EDS test, the adsorption of TOC was evaluated in different spiked drinking water. The adsorption data were simulated using isotherm models. The pore size distributions and pore volume of synthesized nano-composite were measured using multiple point nitrogen gas adsorption/desorption analysis. In addition, central composite design (CCD) was applied to optimize the effects of the operating parameters, including contact time (5-60 min), adsorbent dose (0.5-4 g/l), and initial concentration of TOC (2-20 ppm), on responses which were adsorption rates (mg/kg). The FE-SEM micrographs showed that the dispersion of the nano-Tio(2) particles was relatively good and only few aggregations exist. The total pore volume of synthesized nano-composite was 2.06 cm(3)/g (p/p(0) = 0.98) with an average pore diameter of 2.48 nm and a surface area of 51.52 m(2)/g. Optimized conditions of initial TOC concentration, adsorbent dose, and contact time were found as 11.00 mg/L, 2.25 g/L, and 32.50 min, respectively. The isotherm evaluations revealed that the equilibrium data for TOC removal using PP/TiO2 nano-composite could be fitted with the Langmuir model. The obtained results showed that the PP/TiO2 nano-composite can be effectively used to remove TOC from relatively polluted water.