High crystallinity nano-biochar synthesized from lotus leaf wastes for uptake of dye molecules from synthetic and real wastewater

This article investigates the potential of lotus leaves-derived nano-biochar in eliminating methyl violet (MV) dye from synthetic and real textile wastewater. The surface of nano-biochar was characterized by TEM, BET, FTIR, XRD, DLS, and FESEM analyses. The BET surface area of nano-biochar was 456.3 m2.g-1, demonstrating an excellent specific surface area. The highest biosorption efficiency and maximum biosorption capacity of MV were 96.3% and 526.3 mg/g, respectively, which were obtained at pH 10, equilibrium time of 200 min, adsorbent concentration of 0.5 g/L, MV ion concentration of 150 ppm, and temperature of 50 oC. Also, the mechanism of the biosorpiton process shows that the process is endothermic. Based on R2 and RSME error values, the biosorpion process followed the pseudo-first-order and Langmuir models, indicating that monolayer biosorption of MV molecules on the biochar surface is dominant. Besides, nano-biochar was successfully reused in three steps with high efficiency. The impact of interference ions such as methylene blue, methyl orange, crystal violet, and brilliant blue on MV sorption was investigated and the outcomes revealed that nano-biochar has a remarkable ability to simultaneously eliminate these dye molecules. Additionally, nano-biochar could eliminate COD, BOD5, turbidity, TDS, and EC from a real textile wastewater with high efficiency. Overall, biochar nano-powder, owing to its high reusability, high sorption capacity, easy synthesis, and low-cost, can be considered an ideal option for industrial application.