Polystyrene-NiO-CNT composite ball and film for photocatalytic degradation of methylene blue dye

Immobilization of photocatalysts on the solid support is important for environmental pollutant removal. We have prepared NiO-CNT composite photocatalyst following co-precipitation and catalytic pyrolysis method. The polystyrene-NiO-CNT composite film was prepared by adding 200 mg of NiO-CNT in 10 mL chloroform and different wt% (30%, 50%, and 70%) of waste expanded polystyrene (WEPS), and subsequently, the film was cast on a petri-dish with a film thickness of 0.45 mm. The charcoal balls (weight = 2 g, diameter = 2 cm) were coated with PS-NiO-CNT (30% PS) solution. The prepared photocatalyst powder, ball, and film, were compared for degradation of 100 mL methylene blue (MB) dye (10 mg/L). It was found that the powder and ball catalyst has exponential degradation, whereas the film catalyst has linear degradation nature. The powder sample (200 mg/100 mL) can degrade similar to 96% of MB while a ball can degrade similar to 86%, a film with 30% PS can degrade similar to 81% within 4 h. The film and ball are magnetic, easily recyclable, and can be reused up to the 4th cycle without an appreciable loss (< 10%) of degradation efficiency. Copyright (C) 2022 Elsevier Ltd. All rights reserved.