Using a promising biomass-based biochar in photocatalytic degradation: highly impressive performance of RHB/SnO2/Fe3O4 for elimination of AO7

Abstract

The release of industrial dyes into the environment has recently increased, resulting in harmful effects on people and ecosystems. In recent years, the use of adsorbents in photocatalytic nanocomposites has attracted significant interest due to their low cost, efficiency, and eco-friendly physical and chemical characteristics. Herein, Acid Orange 7 (AO7) removal was investigated by photocatalytic degradation using Rice Rusk Biochar (RHB), Tin (IV) Oxide (SnO 2 ), and Iron Oxide (Fe 3 O 4 ) as heterogeneous nanocomposite. After the preparation of RHB, the nanocomposite was synthesized and characterized using Field Emission Scanning Electron Microscope (FESEM), X-ray Powder Diffraction (XRD), Brunauer-Emmett-Teller (BET), and Fourier-Transform Infrared Spectroscopy (FT-IR). To optimize the elimination of AO7 by the One-Factor-At-a-Time (OFAT) method, effective parameters including mixing ratio (RHB:SnO 2 :Fe 3 O 4 ), dye concentration, solution pH, and nanocomposite dose were studied. The results showed that the removal efficiency of AO7 after 120 min under the optimal mixing ratio of 1:1.5:0.6, dye concentration of 75 mg/l, solution pH of 4, and nanocomposite dose of 0.7 g/l was 92.37%. Moreover, Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal rates were obtained at 82.22 and 72.22%, respectively. The Average Oxidation State (AOS) and Carbon Oxidation State (COS) of the AO7 solution were increased after the process, indicating biodegradability improvement. Various scavenger effects were studied under optimal conditions, and the results revealed that O 2 − and H + reactive species play a crucial role in the photocatalytic degradation of AO7. The reusability and stability of nanocomposite were tested in several consecutive experiments, and the degradation efficiency was reduced from 92 to 79% after five consecutive cycles. It is expected that this research contributes significantly to the utilization of agricultural waste in photocatalytic nanocomposites for the degradation of environmental pollutants.

Degradation of 2,4-dinitrotoluene in aqueous solution by dielectric barrier discharge plasma combined with Fe–RGO–BiVO4 nanocomposite

“…( 40 ) and ( 41 ), respectively, to assess the level of oxidation and efficacy of the oxidative process. As may be seen, to calculate those indicators, the COD and DOC values have been measured at several reaction times 59 , 60 . …”

“…The AOS value varies between + 4 and − 4 with the highest value (+ 4) representing CO 2 , the most oxidized form of Carbon, and the lowest value (− 4) representing CH 4 , the most reduced form of Carbon. Only the solution's organic compounds are taken into account by the AOS 59 , 60 . It's important to point out that in COS calculations, even the that is removed from the reaction solution is included 60 – 62 .…”

“…Only the solution's organic compounds are taken into account by the AOS 59 , 60 . It's important to point out that in COS calculations, even the that is removed from the reaction solution is included 60 – 62 . Accordingly, since AOS and COS are indicative of qualitative changes in the solution that result in toxicity and biodegradability, they can serve as indirect indicators of biodegradability.…”

Photocatalytic Degradation of Rhodamine-B and Water Densification via Eco-Friendly Synthesized Cr2O3 and Ag@Cr2O3 Using Garlic Peel Aqueous Extract

“…After 60 min, the degradation percentage climbed slightly to 97.5%. Due to the active sites on the Cr 2 O 3 surface filling up and the resultant slower rate of degradation, the amount of RhB degradation increased steadily [62]. After 60 min, the maximum degradation of 97.5% was achieved.…”