Capture of CO2 on γ-Al2O3 materials prepared by solution-combustion and ball-milling processes.

UNLABELLED: A series of porous γ-Al2O3 materials was prepared by solution-combustion and ball-milling processes. The as-prepared powders were physicochemically characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 physisorption measurements and their performances in CO2 adsorption at different pressures (0.5 to 1.5 MPa) and temperatures (40 to 60ºC) were investigated. It was found that γ-Al2O3 synthesized by the solution-combustion process and ball milled at 10 hr exhibited the best CO2 adsorption performance at 60ºC and 1.5 MPa, achieving a maximum of 1.94 mmol/g compared to the four studied materials, as a result of their interesting microstructure and surface properties (i.e., nanocrystallinity, specific surface area, narrow pore size distribution, and large total pore volume). Our study shows that the γ-Al2O3 prepared by solution combustion followed by ball milling presents a fairly good potential adsorbent for efficient CO2 capture. IMPLICATIONS: In this work, γ-Al2O3 materials were successfully obtained by solution combustion and modified via ball milling. These improved materials were systematically investigated as solid adsorbents of accessible surface areas, large pore volumes, and narrow pore size distribution for the CO2 capture. These studied solid adsorbents can provide an additional contribution and effort to develop an efficient CO2 capture method as means of alleviating the serious global warning problem.

Chromium (VI) adsorption on boehmite.

Boehmite was synthesized and characterized in order to study the adsorption behavior and the removal of Cr(VI) ions from aqueous solutions as a function of contact time, initial pH solution, amount of adsorbent and initial metal ion concentration, using batch technique. Adsorption data of Cr(VI) on the boehmite were analyzed according to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption models. Thermodynamic parameters for the adsorption system were determinated at 293, 303, 313 and 323K temperatures. The kinetic values and thermodynamic parameters from the adsorption process show that the Cr(VI) ions adsorption on boehmite is an endothermic and spontaneous process. These results show that the boehmite could be considered as a potential adsorbent for chromium ions in aqueous solutions.

Exposure to total and respirable minerals in an abrasive manufacturing facility.

This work describes the qualitative and quantitative determination of some elements found in emery dust in air from abrasive manufacturing industry materials. The analysis of samples was done by neutron activation analysis and atomic absorption spectrometry techniques. Silicon, aluminum, chromium, iron, magnesium, calcium, bromine, manganese, zinc, lead, nickel, and vanadium elements were found. The concentration of silicon in the sampling area was 15.87 +/- 0.87 mg/m3 and 7.93 +/- 0.45 mg/m3 to personal samples, which exceed the threshold limit values (TLV). The other elements were present in concentrations lower than their respective TLVs.