Indirect Measurement of Variables in a Heterogeneous Reaction for Biodiesel Production.

This research focuses on the development of a state observer for performing indirect measurements of the main variables involved in the soybean oil transesterification reaction with a guishe biochar-based heterogeneous catalyst; the studied reaction takes place in a batch reactor. The mathematical model required for the observer design includes the triglycerides' conversion rate, and the reaction temperature. Since these variables are represented by nonlinear differential equations, the model is linearized around an operation point; after that, the pole placement and linear quadratic regulator (LQR) methods are considered for calculating the observer gain vector (x).

High Adsorption of Hazardous Cr(VI) from Water Using a Biofilter Composed of Native on Alginate Beads.

Most conventional methods to remove heavy metals from water are efficient for high concentrations, but they are expensive, produce secondary pollution, and cannot remove low concentrations. This paper proposes a biological system to remove Cr(VI) from aqueous solutions; the biofilter is composed of a native immobilized in calcium alginate beads. Lab experiments were conducted in batch reactors, considering different operating conditions: Cr(VI) concentration, temperature, pH, and time.

Physicochemical Characteristics of Biofuel Briquettes Made from Pecan () Pericarp Wastes of Different Particle Sizes.

Pecan nut () pericarp is usually considered as a waste, with no or low value applications. Its potential as a densified solid biofuel has been evaluated, searching for alternatives to generating quality renewable energy and reducing polluting emissions in the atmosphere, based on particle size, that is an important feedstock property. Therefore, agro-industrial residues from the pecan nut harvest were collected, milled and sieved to four different granulometry: 1.

Synthesis and Surface Modification of Small Pore Size Zeolite W for Improving Removal Efficiency of Anionic Contaminants from Water.

The presence of regulated inorganic contaminants in water such as AsO and PO anions, is becoming a relevant environmental research topic. The harm that these anions cause to human health and the ecosystem have been reported in several works. The adsorption processes using low-cost materials, such as zeolites, have proven to be an option to removal hazardous contaminants from water.

Production of fatty acid methyl esters and bioactive compounds from citrus wax.

Citrus wax is a waste generated during the purification process of the citrus essential oil. A lot of citrus wax wastes are globally produced, despite this, its composition and properties are not well known. Here we present comprehensive results proving the chemical composition and the physical properties of citrus wax.

Interaction Between Cobalt Ferrite Nanoparticles and Aspergillus niger Spores.

The immobilization of microorganisms has been reported as an alternative to improve the efficiency of processes such as fermentation, anaerobic digestion, bioadsorption, and many others. Since the kinetics of bioprocesses are governed by the adsorbent/adsorbate interaction, it is important to know the mechanisms of interaction between biological materials and supports. This could help to define optimal operating conditions.

Bactericidal In-Vitro Effect of Zinc Ferrite Nanoparticles and the Orange Wax Extracts on Three Phytopathogen Microorganisms.

Phytopathogenic bacteria affect a wide variety of crops, causing significant economic losses. Natural biocides are the alternative to chemical methods of phytopathogens control. The goal of the present study is the evaluation of the biocidal activity of the following: 1) the extract of orange wax (EOW); 2) zinc ferrite nanoparticles (ZF-NPs); 3) the EOW adsorbed on the ZF-NPs; and 4) the EOW/ZF-NPs washed with 40% ethanol.

Ultrasound-assisted sol-gel synthesis of ZrO.

Synthesis of tetragonal ZrO by both conventional sol-gel and ultrasound-assisted sol-gel methods and using a non-ionic surfactant Tween-20, was performed. A porous microstructure composed of nanometric particles was observed. Tetragonal ZrO was obtained using a low heat treatment temperature of powders, 500°C by both methods.