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A novel iron-modified biochar (FMBC) derived from rice straw was synthesized using FeCl3 modification for efficient As(V) removal from aqueous solution. FTIR and SEM-EDX analyses were carried out to determine the mechanism involved in the removal process and also demonstrated that Fe had loaded successfully on the surface of modified biochar. The iron-modified biochar showed higher arsenic removal ability than the raw biochar. The iron-modified biochar showed a maximum adsorption with an initial solution pH of 5.0. Moreover, for the tested biochar, the As(V) removal kinetics data were well fitted by the pseudo-second-order model. Furthermore, the As(V) removal data upon being well fitted by the Langmuir model showed the maximal removal capacity of 28.49 mg/g. The simple preparation process and high adsorption performance suggest that the iron-modified biochar derived from rice straw could be served as an effective, inexpensive, and environmentally sustainable adsorbent to replace typical granular activated carbon (AC) for As(III) removal from aqueous solution.

Carbon and iron co-doped titanium dioxide catalyst coated on activated carbon (Fe-C-TiO2/AC) was successfully synthesized using the sol-gel method, followed by hydrothermal treatment. Commercial activated carbon was treated by HNO3 prior to being coated by the as-synthesized catalyst. The composite was characterized by XPS, XRD, UV-Vis spectrophotometry, IR, TEM, HR-TEM, and BET. The performance of the supported catalysts was evaluated in the degradation of rhodamine B (RhB) in the solution under visible-light irradiation. The results showed that, with the appropriate amount of activated carbon, prepared Fe-C-TiO2/AC catalysts exhibited higher catalytic activities and Fe-C-TiO2/AC system showed the best performance. The photocatalytic degradation efficiency of Fe-C-TiO2/AC was enhanced due to the synergistic effect between AC (adsorption effect) and Fe-C-TiO2 (photocatalysis effect). This facilitated the photocatalytic degradation of RhB by Fe-C-TiO2.

The α-Fe2O3/g-C3N4 heterojunction was synthesized using a facile ultrasonic method using alpha hematite (α-Fe2O3) and graphitic carbon nitrite (g-C3N4) as precursors. These samples were characterized by advanced techniques such as SEM, EDX, XRD, PL and UV-Vis to investigate their morphology, elemental composition, crystalline structures and optical properties. Photocatalytic performance of these synthesized materials was investigated via degradation of tetracycline in the aqueous environment upon excitation of visible light. Obtained experimental results indicated that the synthesized α-Fe2O3/g-C3N4 sample exhibited high photocatalytic activity for tetracycline degradation. The improvement in photocatalytic efficiency of the synthesized α-Fe2O3/g-C3N4 was due to the Z-scheme mechanism, which effectively prevented electron-hole recombination or increased electron-hole separation efficiency for photocatalysis. The photocatalytic tetracycline degradation by the α-Fe2O3@g-C3N4 followed the pseudo first-order model. The optimized pH for its photocatalysis was found to be 8. Finally, the synthesized material exhibited high stability after five recycling cycles. [ABSTRACT FROM AUTHOR]

Thermally stable perovskite-like SmFeO3 powders were obtained by the co-precipitation method using (NH4)2CO3 as a precipitating agent; their physicochemical, optical, and magnetic properties were characterized to preliminary evaluate their potential applications. It was found that a well-crystallized pure-phase SmFeO3 will be obtained when the calcination temperature (tc) reaches 850°C. The average size of SmFeO3 crystallites was about 45, 55, and 64 nm for the SmFeO3-750, -850, and -950 samples, respectively. The orthorhombic structure was distorted, as evidenced by the varied unit cell volume (from 233.35·10−3 to 233.07·10−3 nm3) and microstrain (from 2.02·10−3 to 0.009·10−3) in dependence on tc (from 750 to 950°C), respectively. The synthesized SmFeO3 samples exhibited paramagnetic properties, with the coercive field (Hc) in the range of 250–750 Oe. Moreover, the obtained materials have direct bandgap energies with values below 3.06 eV. [ABSTRACT FROM AUTHOR]