Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

The overall goal of this experiment is to develop a green methodology for the facile synthesis of stabilized ultra-fine aluminum hydroxide particles, which can be used to effectively introduce aluminum hydroxide or aluminum oxide onto a wide variety of materials. The newly developed synthesis produces a novel phase of ultra-fine aluminum hydroxide by implementing arginene as a mild base source. The main advantage of this technique is taking arginene, an edible basic amino acid, to neutralize aluminum chloride, to form ultra-fine aluminum hydroxide, and stabilize the particles.

We solve agglomeration. The ability to prepare stabilized ultra-fine aluminum hydroxide paves the way for further structural and mechanistic studies, in attempts to better understand hydrolysis of aluminum monomers to bulk aluminum hydroxide. Demonstrating the procedure will be our intern, Viktor Dubovoy.

To begin this procedure, dissolve 1.4 grams of aluminum chloride hexahydrate in 5.822 grams of deionized water. Slowly add 2.778 grams of L-arginine under magnetic stirring. Once the L-arginine is complete dissolved, heat the solution at 50 degrees celsius for 72 hours.

Then, prepare gel permeation chromatography column by packing the gel in successive steps of adding gel, and then allowing water to flow through the column, to ensure proper packing. Pack the gel to approximately 80%of the column. Next, use an HPLC pump with a 10ml injector loop, to introduce 10ml of the synthesized ultra-fine aluminum hydroxide suspension into the column.

Collect the majority of the peak-1 fraction over 100 minutes. Once a peak emerges on the LI detector, collect the LU end in 30 minute intervals. After this, add one weight percent solution of sodium chloride drop-wise to 10ml of the purified ultra-fine aluminum hydroxide, to induce precipitation.

To begin, use a vacuum oven to activate one gram of MCM-41 at 120 degrees celsius under vacuum for three hours. Next, combine 9.6926 grams of aluminum chloride hexahydrate and 40.3074 grams of deionized water. Add 0.74 grams of activated MCM-41 to this aluminum chloride solution.

Mix for one hour, to ensure homogeneity of the aluminum chloride diffused throughout the MCM-41 channels. Slowly add L-arginine under stirring, such that the final arginine-aluminum molar ratio is 2.75. Once the mixture is homogenous, heat it to 50 degrees celsius for 72 hours.

After this, use a buchner funnel equipped with qualitative 90mm filter paper circles to filter the solution under vacuum. Wash the obtained aluminum MCM-41 material with excess deionized water. In this study, an ultra-fine aluminum hydroxide suspension is prepared, via the controlled titration of aluminum aqua acid with L-arginine.

Magic angle spinning and MR analysis of the prepared aluminum MCM-41 material shows the presence of both octahedral and tetrahedral aluminum environments, which are commonly observed in mesoporus silica-modified aluminum species. Bulk and surface elemental composition data suggests that most of the aluminum penetrated into the pores, as opposed to building up on the surface. Small angle X-ray diffraction patterns are measured before and after aluminum loading, and are indexed based on hexagonal symmetry.

Lattice reflections of 100, 110, 200 are observed in both samples, indicating that the insertion of aluminum had no significant impact on the highly-ordered porosity of MCM-41. Transmission electron microscopy of aluminum MCM-41 particles reveals that the silica framework remains intact after loading aluminum hydroxide particles. This technology can be feasibly scaled to synthesize commercial quantities of ultra-fine aluminum hydroxide, or aluminum functionized high-grade materials.

This acid synthesis is not just extendable to aluminum hydroxide. It is also extendable to other metal oxides, which has far reaching applications in drug-delivery, catalysis, and personal care products. Why the synthesized repeat the amino acids but to generate the same purity and yield.