Zn2+ Modified Activated Carbon from Spent Mushroom Substrate for Organic Wastewater Treatment

Abstract

The booming development of edible mushroom industry has led the disorderly accumulation of spent mushroom substrate, resulting in serious environmental pollutions. In this work, a physical adsorption strategy including three steps of “turning waste into treasure-removal of pollutants-adsorption mechanism” have been provided to solve the environmental problems caused by spent mushroom substrate and organic pollution simultaneously. A series of environment-friendly Zn2+ modified activated carbon (AC) with adequate adsorption capacity are prepared by using spent mushroom substrate as raw material. The X-Ray Diffraction results indicate weak graphitization of Zn2+ modified AC sample during the calcination process. Efficient removal of Rhodamine B, Amoxicillin and Cefixime are attained with removal efficiencies 95, 75, and 88% after 120 min over Zn2+ modified AC calcinated at 600 ℃ (Zn-AC-600), respectively. While the maximal adsorption capacity qmax for Rhodamine B, Amoxicillin and Cefixime towards Zn-AC-600 sample is about 202, 123, and 130 mg·g-1, respectively. The adsorption process of all pollutants is found to match well with the pseudo-second-order kinetics. Zeta potential measurements reveal possible electrostatic attraction between Rhodamine B, Amoxicillin, Cefixime and the synthesized AC samples. This work may provide an effective strategy toward beneficial recycling of spent mushroom substrate wastes and remove pollutants from water.

Keywords: Activated carbon, Spent mushroom substrate, adsorption, Organic wastewater, Calcination