Organic wastewater causes serious environmental pollution, and catalytic oxidation is promising technique for wastewater treatment. Developing green and effective catalysts is currently challenging. In this work, green synthesis of nano zerovalent iron loaded onto porous biochar derived from popcorn is conducted, and catalytic oxidation of Rhodamine B (RhB) is evaluated in the presence of H2O2. Effect of process factors is examined on catalytic performance for RhB removal. The mechanism of RhB removal is discussed by characterizations (Fourier transform infrared spectra and Raman) and UV–vis spectra. RhB removal is improved with high catalyst dosage, low initial RhB concentration, and high reaction temperature, while it is slightly influenced by carbonization temperature of biochar, H2O2 dosage and pH value. Under conditions of BC-250 1.0 g/L, H2O2 0.01 mol/L, pH 6.1, and temperature 30 °C, the removal rate of RhB is 92.27% at 50 min. Pseudo first-order kinetics is used to fitting experimental data, and the activation energy for RhB removal in BC-250/H2O2 system is 39 kJ/mol. RhB removal in BC-250/H2O2 system can be attributed to adsorption effect and catalytic oxidation with the dominant role of hydroxyl radical. This work gives insights into catalytic oxidation of organic wastewater using green catalyst.

Green catalyst derived from zero-valent iron onto porous biochar for removal of Rhodamine B from aqueous solution in a Fenton-like process
    Abstract
    1 Introduction
    2 Materials and methods
        2.1 Catalyst synthesis
        2.2 Characterizations
        2.3 Catalytic performance
    3 Results and discussion
        3.1 Catalytic oxidation of RhB by different biochar
        3.2 Effect of catalyst addition on RhB oxidation
        3.3 Effect of H2O2 addition on RhB oxidation
        3.4 Effect of initial RhB concentration on RhB oxidation
        3.5 Effect of pH value on RhB oxidation
        3.6 Effect of reaction temperature on RhB oxidation
        3.7 Catalytic mechanism
    4 Conclusions
    References

• Chongqing Wang(School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China)
• Pau Loke Show(Department of Chemical Engineering, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates, Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia)
• Xiuxiu Zhang(School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China)
• Yijun Cao(School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China)
• Yasser Vasseghian(Department of Chemistry, Soongsil University, Seoul 06978, South Korea, School of Engineering, Lebanese American University, Byblos, Lebanon, Department of Sustainable Engineering, Saveetha School of Engineering, SIMATS, Chennai 602105, India)