
Publication of Scientific Articles
Here are the latest publications conducted by interns and researchers from CNETE that were published this summer in scientific journals. We congratulate Antonio Avalos Ramirez, Beatriz Delgado Cano, as well as the three interns responsible for the writing: Mariana Valdez Castillo, Mohamed Fodil, and Meriem Merah.
High biosorption of cationic dye onto a novel material based on paper mill sludge
M. Merah· C. Boudoukha · A. Avalos Ramirez · M. Fahim Haroun · S. Maane
The valorization of paper mill sludge (PMS) is the main goal of this study. The emissions of PMS continue to increase at global scale, especially from packaging paper and board sectors. The raw sludge was used to prepare an adsorbent to remove toxic pollutants from wastewater, the methylene blue (MB), an organic dye. Firstly, the physico-chemical characterization of PMS was done determining the crystalline phases of PMS fibers, the content of main elements, and the pH zero point charge, which was determined at around pH 7. The adsorption of MB on PMS powder was studied at 18 °C with an agitation of 200 rpm, being the best operating conditions 30 min of contact time, 250 mg L−1 of initial MB concentration and 0.05 g in 25 mL of adsorbent dose. Experimental data of MB adsorption was fitted to Langmuir and Freundlich isotherm equations. The Langmuir model was more accurate for the equilibrium data of MB adsorption at pH 5.1. The PFOM and PSOM were adjusted to experimental adsorption kinetics data, being PSOM, which describes better the MB adsorption by PMS powder. This was confirmed by calculating the maximum adsorption capacity with PSOM, which was 42.7 mg g−1, being nearly similar of the experimental value of 43.5 mg g−1.

The analysis of adsorption thermodynamics showed that the MB was adsorbed exothermically with a ΔH0 = − 20.78 kJ mol−1, and spontaneously with ΔG0 from − 0.99 to − 6.38 kJ mol−1 in the range of temperature from 291 to 363 K, respectively. These results confirm that the sludge from paper industry can be used as biosorbent with remarkable adsorption capacity and low cost for the treatment of wastewater. PMS can be applied in the future for the depollution of the effluents from the textile industry, which are highly charged with dyes.

Co-Fermentation of Agri-Food Residues Using a Co-Culture of Yeasts as a New Bioprocess to Produce 2-Phenylethanol
M. Valdez Castillo · S. Kaur Brar · S. Arriaga · J-F. Blais · M. Heitz · A. Avalos Ramirez

Whey is a dairy residue generated during the production of cheese and yogurt. Whey contains mainly lactose and proteins, contributing to its high chemical oxygen demand (COD). Current environmental regulations request proper whey disposal to avoid environmental pollution. Whey components can be transformed by yeast into ethanol and biomolecules with aroma and flavor properties, for example, 2-phenyethanol (2PE), highly appreciated in the industry due to its organoleptic and biocidal properties. The present study aimed to valorize agri-food residues in 2PE by developing suitable bioprocess. Cheese whey was used as substrate source, whereas crab headshells, residual soy cake, and brewer’s spent yeast (BSY) were used as renewable nitrogen sources for the yeasts Kluyveromyces marxianus and Debaryomyces hansenii. The BSYs promoted the growth of both yeasts and the production of 2PE in flask fermentation. The bioprocess scale-up to 2 L bioreactor allowed for obtaining a 2PE productivity of 0.04 g2PE/L·h, twofold better productivity results compared to the literature. The bioprocess can save a treatment unit because the whey COD decreased under the detection limit of the analytical method, which is lower than environmental requirements. In this way, the bioprocess prevents environmental contamination and contributes to the circular economy of the dairy industry.

Adsorption of Lead from Wastewater Using Olive Leaf Powder as Biosorbent
M. Fodil · S. Maane · A. Avalos Ramirez · B. Delgado Cano · M. F. Haroun
The residues of olive present high potential to be valorized as biosorbent. In the present study, the properties of olive leaf powder (OLP) as biosorbent of lead ions present in wastewater were analyzed. Firstly, the OLP was characterized by determining its physio-chemical properties using analytical methods as X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, pH of zero-point charge. The optimal operating conditions are determined following adsorption tests, using pH 7.5, contact time5 minutes, temperature 20°C, and biosorbent content of 2 g.L -1 , for a lead ions concentration of 80 mg.L -1 . The Langmuir isotherm model is fitted the best to experimental data with an adsorption capacity q e = 68.96 mg.g -1 . The adsorption is a pseudo-second order kinetics reactional system and the study of thermodynamic parameters revealed that the adsorption of lead on OLP is exothermic and spontaneous.
