Converting waste polystyrene foam into new value-added materials: A large-capacity scavenger to remove cationic dyes and heavy metals

Waste white foam, toxic dyes, and metal ions are difficult to degrade in the ecological environment, posing a serious threat to human health and natural beauty, it is of great significance to design a functional material to jointly solve these problems. This study provided a facile approach to convert waste polystyrene foam into a new acid anhydride modified polystyrene adsorbent (PS-MA) for the dyes and heavy metals removal from aqueous solution. The as-obtained absorbent was characterized by Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, energy dispersive spectroscopy, Brunauer Emmett Teller method, and X-ray photoelectron spectroscopy. Influencing factors are including, pH, dye concentration, contact time and temperature on the adsorption of methylene blue (MB), safranine T (ST), and Cu(II) were systematically studied. Boehm titration showed that the content of surface carboxyl groups reached 4.53 mmol/g. The maximum adsorption capacity had reached 1405.37 mg/g for MB, 2269.33 mg/g for ST, 65.03 mg/g for Cu(II). Moreover, the kinetic data were in good agreement with the pseudo-second-order model and closed to adsorption equilibrium at 20 min. After five times of recycling experiments and the application of mixed dye wastewater with salinity, PS-MA showed excellent stability and removal ability. Abundant efforts revealed a broad application prospect of PS-MA materials in water remediation.

Automated summary

This study successfully converted waste polystyrene foam into a new acid anhydride modified polystyrene adsorbent for the removal of dyes and heavy metals from water. The as-obtained PS-MA material showed excellent adsorption performance and stability, suggesting a broad application prospect in water remediation.