Adsorptive removal of methylene blue, tetracycline and Cr(VI) from water using sulfonated tea waste

Biomass-derived adsorbents are constantly explored for wastewater treatment due to significant advantages such as easy scale-up, cost-effectiveness and environmental-friendliness. Here we report the exceptionally high adsorption capability of sulfonated spent tea leaves towards environmental pollutants such as methylene blue, tetracycline and Cr(VI) is reported through this article. The carbonized form of organic biomass derived from sulfonated tea waste (STW) exhibited unusually high adsorption capacities for methylene blue (1007 mg/g), tetracycline (381 mg/g) and Cr(VI) (438 mg/g) at room temperature. The effect of dosage, time, pH and temperature on the adsorption was systematically investigated. The Cr-adsorbed STW samples were characterized using Xray photoelectron spectroscopy, electron spin resonance spectroscopy, and Small-angle X-ray scattering (SAXS). Inductively Coupled Plasma Optical Emission Spectrometry (ICPOES) and UV-Vis spectroscopy were used to analyze the water samples. A continuous-flow water filter was also developed based on the tea-waste adsorbent to demonstrate its ability to purify waste-water. Such high adsorption of pollutants using a cheaper adsorbent like STW makes it a viable material for commercial-scale water purification. (C) 2018 Elsevier B.V. All rights reserved.