Synergistic effect of Trichoderma reesei cellulases on agricultural tea waste for adsorption of heavy metal Cr(VI)

This is the first attempt to study the synergistic effect between Trichoderma reesei   cellulases and the abundant agricultural tea waste in absorption of heavy metal Cr(VI) as well as its kinetic model development. The properties of tea waste were first analyzed by near infrared spectroscopy (NIR), particle size distribution (PSD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) examination with EDX for comparison between its original (UN-TW) and cellulase-hydrolyzed (TRCEL-TW) conditions. Then, an advanced kinetic model in the form of -d[Cr(VI)]/dt=A[H+]ne-Ea/RT[Cr(VI)]0m, which can successfully predict the time-dependent Cr(VI) concentration of various pHs, initial Cr(VI) concentrations and temperatures was developed. The demonstrated synergistic effects of T. reesei cellulases on tea waste suggested that cellulosic material provides more accessibility area for absorption of heavy metal. This study also provides an alternative approach to remove toxic Cr(VI) from aqueous solutions and extend the utilization of agricultural tea waste.

► Trichoderma reesei   cellulases showed a synergistic effect on tea waste for absorption of heavy metal Cr(VI). ► The biomaterials were characterized by PDS, XPS, SEM-EDX and NIR. ► An advanced kinetic model in the form of -d[Cr(VI)]/dt=A[H+]ne-Ea/RT[Cr(VI)]0m was successfully adopted in the simulation. ► The best conditions for the Cr(VI) reducing capacity in both UN-TW and TRCEL-TW were at 67 °C, pH 1.5 and 200 mg/L of Cr(VI).