Adsorption and photocatalytic degradation of bisphenol A by low-cost carbon nanotubes synthesized using fallen leaves of poplar

Abstract

Bisphenol A (BPA) is an endocrine disruptor and the removal of it from contaminated water is a primary environmental issue. Here, carbon nanotubes (CNTs) were synthesized by heating leaves of poplar to 450 °C in air. The outer and inner diameters of CNTs were about 77.5 nm and 40.1 nm, which contained C, O, Na, Zn, Cu, Ca, K, Cl, and S. The effects of adsorption and photocatalysis on BPA (initial concentration was 10 mg L⁻¹) by CNTs (10 mg CNTs were added into 1 L BPA solution) synthesized using leaves of poplar were studied. The results show that without CNTs, the degradation of BPA was about 24.5 ± 4.7% in 180 min with solar light irradiation. The complete equilibration time of adsorption/desorption of BPA onto the surface of CNTs was within 30 min, and approximately 19.7 ± 0.9% BPA was adsorbed by CNTs. Afterwards, the photodegradation efficiency of BPA was increased to 74.8 ± 3.9% with the combination of CNTs and solar light irradiation for 180 min. The photocatalytic property on BPA was caused by CNTs and the metal oxide on the surface of them. The methods have positive effects on solving environmental and ecological problems as well as the problem of high cost for preparation of photocatalyst.