Characterizing and optimizing adsorption for olive mill wastewater processing in Loukkos, Morocco.

The present research consists of studying the characterization and treatment of the olive mill wastewater (OMWW) resulting from the olive industries of the region of Loukkos, Morocco. According to the national plan for green Morocco, the annual volumes of OMWW discharges increase with the expansion of the areas of olive plantations compared to agricultural activities. The study of the organic, mineral, and microbiological composition of the obtained OMWW showed that they are rich in microbiological (FMAT, Let M., and B.L.), mineral (total Kjeldhal nitrogen, orthophosphate, total phosphorus, sodium, potassium, calcium, copper, iron, zinc, manganese, and lead ions), and organic (COD, BOD5, and polyphenols) micropollutants with very high percentages that are higher than the standards in force. The treatment used in this study is the combined process of aerated lagooning/adsorption using powdered activated carbon after optimization of the experimental parameters (mass concentration of activated carbon (AC) and agitation rapidity (Ar)) by experiment design method. The obtained physicochemical parameters, such as pH, total suspended solids (TSS), chemical oxygen demand (COD), rate of discoloration, and polyphenol content of raw OMWW, were 4.87, 0.63, 80.3, 0.8, and 1.45 g/l, respectively. The results of these parameters for the treated OMWW were obtained in the order of 6.10, 0.22, 28, 0.28, and 0.44 g/l for pH, TSS, COD, discoloration rate, and polyphenol content, respectively. These results show that the proposed treatment significantly reduced acidity, TSS, COD, discoloration rate, and polyphenol contents, with a performance of about 25.26, 65, 65.13, 65, and 69.65%, respectively. This indicates that there is significant performance in the processing of exploited OMWW.

Aerated lagoon/adsorption combination method for the treatment of olive mill wastewater: optimizing parameters using study design.

The current study focuses on investigating how to improve the efficacy of the combined process of aerated lagooning and adsorption for the treatment of olive mill wastewater (OMWW) from the olive industries in the Loukkos region using the design of experiments approach. The latter made it possible to optimize the experimental conditions, such as the mass concentration of lime, the mass concentration of powdered activated carbon (AC), and the speed of agitation (Va), which are required for the envisaged treatment, in order to control the results after the evaluation of the necessary physicochemical parameters, namely pH, total suspended solids (TSS), chemical oxygen demand (COD), rate of discoloration, and content of polyphenols. The experimental conditions necessary to carry out this study were between 1.4 and 1.75 g/l for AC, between 23 and 32 rpm for the stirring speed, and between 0.88 and 1.3 g/l for the mass concentration of lime. The results of this experiment showed that treating OMWW with the prototype II after adding lime to the mixture resulted in an estimated 85% reduction in the analyzed parameters. The pH, TSS, COD, discoloration rate, and polyphenol content were all reduced from initial values of 4.87, 0.63 (g/l), 80.3 (g (O2/l)), 0.8%, and 1.45 (g/l), respectively, to final values of 6.92, 0.12 (g/l), 12, 0.16%, and 0.25 (g/l). These results are highly significant when compared to those obtained during the treatment of prototype I using only powdered activated carbon, which showed a reduction rate of around 70%.

Using egg ovalbumin to synthesize pure α-Fe2O3 and cobalt doped α-Fe2O3: structural, morphological, optical and photocatalytic properties.

Nanoparticles of undoped hematite (α-Fe2O3) and Co doped α-Fe2O3 were prepared by a simple, green, and cost-efficient process using Co and Fe chlorides and freshly isolated hen egg white. Several techniques of characterization, such as differential thermal and thermogravimetric analysis (DTA/TG), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), EDS analysis, X-ray diffraction analysis (XRD), and Ultra-violet Visible (UV-Vis) analysis were applied. The incorporation of Co particles into the hematite matrix limits the growth of the α-Fe2O3 crystalline grain and favours the apparition of γ-Fe2O3 phase. SEM analysis reveals that there are no significant morphological differences among α-Fe2O3 and Co-α-Fe2O3 particles, whereas the XPS analysis confirms the existence of Fe and Co particles in the as-prepared samples. The optical study shows a slight reduction of band gap energy for Co doped α-Fe2O3 compared to the non-doped α-Fe2O3, which has shown enhanced visible light adsorption performance. On the other hand, the α-Fe2O3 and Co-α-Fe2O3 nano-photocatalysts with an average crystallite size of 21 and 43 nm respectively, were used to remove the Methylene Blue (MB) dye from aqueous solutions after being exposed to visible light. In a mechanistic study, the radicals OH• and •O2 - were shown to be important in the degradation of MB dye. To optimise the effective parameters on MB dye degradation, the experimental parameters applied in the adsorption experiments, such as pH, photocatalyst dosage, contact time, and temperature, were tested. The optimal conditions were determined as pH = 12, photocatalyst dosage = 0.2 g/L. Degradation efficiency in the optimal conditions is 91.8 % after 120 min of irradiation. The pseudo-first and second orders were used to model the kinetic data. The removal of MB using α-Fe2O3 and Co-α-Fe2O3 photocatalysts matched well with pseudo-second-order reaction kinetics. Furthermore, the thermodynamic study reveals that MB dye adsorption on the Co-Fe2O3 absorbent was an endothermic and spontaneous process.