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    Efficient charge transfer in rheum ribes waste-derived biochar-supported Bi2MoO6 nanocomposites for visible-light-driven photocatalytic degradation of antibiotics
    (Elsevier BV, 2025-11)
    Fatemeh Khezri Shooshtari
    ;
    Mohammad Sina Mohtaram
    ;
    Pegah Roohparvarzadeh
    ;
    Mohammad Mahdi Zerafat
    ;
    HESAM, KAMYAB  
    The sustainable removal of emerging pharmaceutical pollutants from aqueous systems has become a critical environmental challenge, demanding the development of efficient and reusable photocatalysts. Herein, a novel Rheum ribes waste-derived biochar supported Bi2MoO6 (Bi2MoO6/BC) nanocomposite was synthesized and systematically evaluated for visible-light-driven tetracycline (TC) degradation. Structural and morphological analyses (XRD, FTIR, SEM, TEM, and EDX mapping) confirmed the successful anchoring of ultrathin Bi2MoO6 nanosheets onto a porous conductive biochar matrix, providing abundant surface-active sites. Optical and electrochemical characterizations (UV–Vis DRS, PL, EIS, and photocurrent) demonstrated enhanced visible-light absorption, narrowed band gap, quenched photoluminescence, lower charge-transfer resistance, and higher photocurrent density, all indicative of efficient charge separation. RSM optimization using Design-Expert revealed catalyst dosage, initial concentration, and solution pH as decisive parameters, with optimal conditions (1 g L−1, 20 ppm, pH = 6) yielding degradation efficiencies above 95 %. Radical trapping experiments confirmed •O₂− as the dominant species, with •OH and h+ also contributing, and the synergistic mechanism featuring rapid electron transfer to biochar and the subsequent production of reactive radicals ultimately enabled the complete degradation of TC into CO₂ and H₂O.
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    Ultrasonic-assisted synthesis of TiO2/MWCNT/Pani nanocomposite: Photocatalyst characterization and optimization of efficient variables in the degradation of benzene via RSM-CCD
    (Elsevier BV, 2024-01)
    Milad Karamifar
    ;
    Samad Sabbaghi
    ;
    Mohammad Sina Mohtaram
    ;
    Kamal Rasouli
    ;
    Mahdi Mohsenzadeh
    Nowadays, volatile organic compounds (VOCs) are the primary cause of rising contamination in groundwater, surface water, and wastewater. On the other hand, photocatalysis technology is among the best ways to treat wastewater because of its ability to rapidly mineralize a range of pollutants into non-toxic chemicals using sunlight as an energy source and its ecological friendliness. Herein, the TiO2/MWCNT/Pani nanocomposite was synthesized by combining ultrasonic and in-situ polymerization methods to decompose benzene, a prevalent and harmful VOC. The nanocomposite was characterized by XRD, FTIR, BET, SEM, and UV–Vis analysis. The response surface methodology (RSM), based on Central Composite Design (CCD), was used to investigate and optimize the effects of the independent factors on photocatalytic degradation, including initial benzene concentration, catalyst dosage, pH, and light irradiation time. The optimal conditions (benzene concentration = 700 mg. L−1, pH = 6, irradiation time = 80 min, and photocatalyst dosage = 1.5 g. L−1) resulted in maximum benzene degradation (84.90%). Trapping test and EPR analysis were also utilized to detect reactive species, and the findings indicated that the breakdown of benzene through photocatalysis is caused by the presence of hydroxyl radicals (•OH) and superoxide radicals (•O2−). Furthermore, the kinetics of the reaction and the stability of the nanocomposite (4 cycles) were examined. Finally, the results of this study provide convincing evidence for using TiO2/MWCNT/Pani as highly efficient and promising photocatalysts for removing benzene from aqueous solutions.