Characterization of AlFe-pillared Unye bentonite: A study of the surface acidity and catalytic property

Dehydration Isopropyl Alcohol to Diisopropyl Ether over Molybdenum Phosphide Pillared Bentonite

Emissions from gasoline are one of the contributors to air pollution. Diisopropyl ether (DIPE) is an alternative oxygenate additive that can improve gasoline quality, minimizing CO and hydrocarbon gas emissions during combustion. However, there are very few studies on the use of pillared bentonite-based catalysts for DIPE production. This study aims to produce DIPE via dehydration of isopropyl alcohol using a molybdenum phosphide pillared bentonite (MoP-Bentonite) catalyst. The effect of Mo6+ metal concentration on the catalytic activity of isopropyl alcohol dehydration was also investigated. The catalyst that gives the highest DIPE yield will be analyzed by X-ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX), Gas Sorption Analyzer (GSA), and total acidity using the gravimetric method. In addition, the dehydration product will be analyzed by Gas Chromatography-Mass Spectroscopy (GC-MS). The results showed that MoP has been successfully pillared into bentonite and showed an increase in surface area, acidity, and catalytic activity. The highest yield of DIPE was obtained using a 4 mEq/g MoP-Bentonite catalyst with a DIPE yield of 64.5%.

Gels based on calcium alginate/pillared bentonite: structural characterization and their use as cadmium removal agent

In this work, calcium alginate hydrogels with natural and pillared bentonites (0.5 and 5% w/w) were synthetized in two geometries (disks and beads) and their capacity to adsorb cadmium ion from aqueous media was evaluated. Pillarization effect on bentonite morphology was evidenced by SEM, XRD, LD and BET isotherms. Structure and swelling capacity of hydrogels were determined, showing that hydrogels beads with pillared clays presented the higher ability to retain water. Regarding cadmium adsorption capacity, the effect of pH media (3, 5 and 7), the contact time (0 to 320 min.) and the initial cadmium ion concentration (6 to 42 mg/L) were studied employing hydrogel beads. Regardless bentonite type and concentration, the optimal pH cadmium adsorption was 7, reaching the highest adsorption capacity (93%) for hydrogel with 0.5% natural bentonite. Besides, the equilibrium adsorption time was reached at 120 min for all studied hydrogels and experimental data fitted with a pseudo-second order kinetic model.

Biobased composites from agro-industrial wastes and by-products

The greater awareness of non-renewable natural resources preservation needs has led to the development of more ecological high-performance polymeric materials with new functionalities. In this regard, biobased composites are considered interesting options, especially those obtained from agro-industrial wastes and by-products. These are low-cost raw materials derived from renewable sources, which are mostly biodegradable and would otherwise typically be discarded. In this review, recent and innovative academic studies on composites obtained from biopolymers, natural fillers and active agents, as well as green-synthesized nanoparticles are presented. An in-depth discussion of biobased composites structures, properties, manufacture, and life-cycle assessment (LCA) is provided along with a wide up-to-date overview of the most recent works in the field with appropriate references. Potential uses of biobased composites from agri-food residues such as active and intelligent food packaging, agricultural inputs, tissue engineering, among others are described, considering that the specific characteristics of these materials should match the proposed application.

The advantages of clay mineral modification methods for enhancing adsorption efficiency in wastewater treatment: a review

This review discusses the recent trends in the research over the last 30 years to use clay minerals in natural and modified forms for removing different toxic organic/inorganic pollutants. The natural and modified forms of clay minerals have an exceptional ability to remove different contaminants. However, the modification methods can improve the clay mineral adsorption properties that consequently increase more adsorption sites and functional groups to adsorb different environmental pollutants. This review shows the importance of modification methods and more extension of novel clay preparation based on nanotechnology which could raise the control of pollution. The syntheses of functionalized clays such as pillared clays and porous clay heterostructures introduce the new class of heterostructure materials with high adsorption capacity, capability, and selectivity. Due to the acceptable properties of heterostructure materials including high specific surface area, thermal and mechanical stability, and the existence of multifunctional groups to selective adsorption, this review collects more literature of research related to environmental protection issues. However, it is expected much attention to get a better understanding of the adsorption mechanism, regeneration, and recovery process of these materials.

Structural modification of nano bentonite by aluminum, iron pillarization and 3D growth of silica mesoporous framework for arsenic removal from gold mine wastewater

The elevated contamination of arsenic species emitted from gold mine activities causes serious environmental problems. The modification of natural bentonite clay to obtain the adsorbent with high porosity, large surface area, and high adsorption capacity creates a new group of porous and heterostructure materials for immobilization of arsenic species from gold mine wastewater under alkaline condition, owing to the gold cyanidation process. There is a limited approach in alkaline mine wastewater, because of the negative surface charge of most adsorbents. In this research, the adsorbability of arsenic under synthetic and real alkaline wastewater was investigated for the first time. The Visual MINTEQ geochemical modeling software was applied to simulate the arsenic species under different pH, temperature and co-existing ions in mine wastewater obtained from dewatering unit in Zarshuran gold mine. Optimized parameters and better adsorbent were initially determined from synthetic alkaline wastewater, then the efficiency of the adsorption process in real alkaline mine wastewater was measured. In real wastewater treatment, the obtained adsorption efficiency higher than 70% with high reusability in the alkaline condition is an appropriated for only one step process. The major mechanism for adsorption was chemical with complexation in rapid and slow diffusion into the active sites.

Synthesis and evaluation of a novel monomeric amine as sodium montmorillonite swelling inhibitor

A novel monomeric amine sodium montmorillonite swelling inhibitor: N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide was obtained from diethanolamine, 1-bromotetradecane, and 1, 2-dibromoethane. N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide was characterized by means of Fourier transform infrared, 1H NMR spectroscopy, elemental analysis, linear swelling tests, particle size distribution tests, X-ray diffraction, and thermogravimetric. Linear swelling tests showed that the swelling height of sodium montmorillonite in 1.0 wt% N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide solution was only 2.0 mm after 16 h (fresh water was 5.0 mm). Particle size distribution tests exhibited that the median diameter and mean particle size of sodium montmorillonite in 1.0 wt% N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide solution obviously increased to 16.1 and 85.4 µm, respectively (fresh water was 8.1 and 21.8 µm). In thermogravimetric tests, in comparison with pure sodium montmorillonite, the decrease of water content in sodium montmorillonite/ N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide indicated N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide expelled the water molecules out of the interlayer, which was beneficial to wellbore stability. Fourier transform infrared spectra of certain concentration N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide/sodium montmorillonite indicated the successful physical adsorption and interaction between N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide with sodium montmorillonite. In addition, the results of X-ray diffraction tests showed the obtained 1.0 wt% N1, N2-ditetradecy- N1, N1, N2, N2-tetrakis (2-hydroxyethyl) ethane-1,2-diaminium bromide solution could remarkably reduce the interlayer distance of wet sodium montmorillonite (from 1.94 to 1.37 nm).