Comparative study on the removal of a local scrap iron tannery made dye from wastewater using alum and rice husk

This work was aimed at removing a local scrap iron dye from tannery wastewater using alum and rice husk. Contact time (0 to 60 min; wastewater dye concentrations: A0 = 0.244 and A0 = 0.48 for alum; A0 = 0.213 and A0 = 0.045 for rice husk), pH (2 to 10; wastewater dye concentration of A0 = 0.045 for rice husk and A0 = 0.073 for alum), mass of adsorbents (0.05 to 1 g; wastewater dye concentration of A0 = 0.184 for alum, A0 = 0.057 for rice husk), temperature (25 to 60 °C; wastewater dye concentration of A0 = 0.079 for rice husk and A0 = 0.048 for alum) and mixtures of the two adsorbents (wastewater dye concentration of A0 = 0.057 and A0 = 0.217) were used to evaluate the effectiveness of these adsorbents in removing color from a local Maroua tannery wastewater. Equilibrium was reached in 10 min with a removal of 54.16% for alum and in 5 min with a removal of 66.66% for biomass. 100% elimination of color was obtained at pH 2 and 4 for rice husk and 73–76% for alum. But the mixture of 0.2 g of alum and 0.1 g of rice husk gave removal rate of 95% with a less concentrated solution against 74.84% for the mixture of 0.1 of alum and 0.2 g of rice husk with concentrated solution. Results of this study shows that substitution or complementing alum a synthetic chemical with rice husk, a biomass highly available at almost no cost can be very efficient in the treatment of tannery wastewater containing dye in a low cost process

Trace Metals Accumulation in Oreochromis niloticus Inhabiting Chari River along the Banda Township in Chad

This study was undertaken to evaluate the trace metals in the fish Oreochromis niloticus inhabiting water of the Chari river, along the Banda township in the middle-Chari Province (Chad). Fishes were sampled at three sites along the river. Trace metals in fish meat were assessed through atomic absorption spectrophotometry. Results indicated that fish meat contents in Pb, Cd, Fe, Cr, Cu and Zn were ranged respectively from 0.482, 0.144, 0.632, 1.110, 1.479 and 4.465 mg/Kg in the dry season, compared to 0.545, 0.179, 0.624, 0.946, 2.917 and 1.813 mg/Kg in the wet season. The bioconcentration factor (BCF) of Pb, Cd, Cr, Cu and Zn was higher than 1, indicating that these heavy metals were indeed accumulated in Oreochromis niloticus. Copper was the most accumulated metal in fish meat during both campaigns. The source of accumulation of these trace metals in fishes was undoubtly from water, and was thought to originate either from the abusive utilization of phytosanitary inputs in agriculture or from nearby wastewater’s factories thrown into the Chari river. It is suggested appropriate controlled measures to be taken to decrease the trace metals pollution of the Chari river, and thereof that of the inhabiting fishes

Synthesis and Investigation of TiO2/g-C3N4 Performance for Photocatalytic Degradation of Bromophenol Blue and Eriochrome Black T: Experimental Design Optimization and Reactive Oxygen Species Contribution

Graphitic carbon nitride (g-C3N4) based photocatalyst was synthesized and the photocatalytic performance was investigated for the removal of Eriochrome Black T (EBT) and Bromophenol Blue (BPB) under UV irradiation. The prepared materials were characterized by SEM-EDX, XRD, Raman, FTIR and DRS. Higher degradation efficiency for the same initial concentrations of EBT and BPB in presence of TiO2/g-C3N4 have been achieved within 160 min of irradiation. The kinetic study showed that the photodegradation of BPB by TiO2/g-C3N4 follows pseudo-first-order kinetics with an R2 value of 0.98. The addition of persulfate (PS) in BPB solution improved the degradation yield from 8.81% to 80.14% within 20 min of UV light irradiation. A Box-Behnken model was developed from three factors and Response surface methodology (RSM) was employed to identify the optimum conditions for the treatment of BPB solution by TiO2/g-C3N4. The experimental values of degradation of BPB agreed with predicted values obtained from central composite design (CCD) analysis with an R2 value of 0.9999. The scavenger study revealed that superoxide radical anion (O2•−) plays a key role (68.89% of contribution) followed by OH• and h+ with 22.40% and 15.55% of contribution, respectively. This study has obviously exhibited the potential of TiO2/g-C3N4 composite as a promising catalyst for photocatalytic purposes

g-C3N4/TiO2 S-scheme heterojunction photocatalyst with enhanced photocatalytic Carbamazepine degradation and mineralization

International audienceIn the present work, UVA light-driven g-C3N4/TiO2 photocatalyst was synthesized for the photodegradation of Carbamazepine (CBZ) in aqueous medium. The morphological, the optical properties and the structure of the TiO2, g-C3N4 and the prepared composites were analyzed using X-ray diffraction (XRD), Nitrogen adsorption-desorption isotherm based on BET, Raman Spectroscopy, Scanning Electron Microscopy (SEM) with EDX, UV-vis Diffuse Reflectance Spectroscopy (UVvis DRS). Optical absorption studies revealed a 2.97 and 2.78 eV of band gap for the developed composites for 10%g-C3N4/TiO2 (A10) and 30%g-C3N4/TiO2 (A30), respectively. The N2 adsorption-desorption isotherm showed an 80.64 and 59.67 m 2 /g of specific surface area for A10 and A30, respectively. Photodegradation studies show that A10 a composite photo-catalyst can eliminate 71.41% of CBZ with 30.38 % of mineralization yield within 360 min of UVA irradiation at optimum conditions (10 ppm of initial CBZ concentration and 0.1 g of 10%g-C3N4/TiO2 loading). The kinetic results showed that the removal of this pollutant nearly followed a First-order kinetic model with a regression coefficient (R 2) values more than 0.98 and a Hight reaction rate constant recorded of 0.0034 min-1 for A10