Adsorption Kinetics of β-Carotene and Chlorophyll onto Acid-activated Bentonite in Model Oil

The textural properties of acid-activated bentonite （AAB）, which were prepared using four different concentrations of sulfuric acid, were analyzed by adsorption-desorption isotherm of nitrogen using an automated specific surface area and porosity analyzer. The total pore volume, specific surface area and average pore diameter of these four kinds of AAB show a regular changing trend, increasing first and then decreasing, the optimum of which can be achieved at a sulfuric acid concentration of 25% （sample A25）. The kinetic analysis of the adsorption of β-carotene and chlorophyll in model oil solutions, namely, xylene and edible oil solution, has been investigated by using AAB. Experimental results indicated that the adsorption data fit the pseudo-second-order model well. The whole adsorption process of the two pigments on AAB was divided basically into two parts： the initial adsorption of pigments was rapid in the first l0 rain, followed by a slower adsorption process till equilibrium was attained at 60 rain. In addition, the amount and rate of adsorption on A25 increase synchronously with the initial pigment concentration and temperature. The results showed that the adsorption kinetics behavior of AAB with respect to the pigments is not influence by the xylene and edible oil solution.

Calcination/acid-activation treatment of an anodic oxidation TiO_2/Ti film catalyst

The aim of this work was to investigate the effects of calcination/acid-activation on the composition, structure, and photocatalytic （PC） reduction property of an anodic oxidation TiO2/Ti film catalyst. The surface morphology and phase composition were examined by scanning electron microscopy and X-ray diffraction. The catalytic property of the film catalysts was evaluated through the removal rate of potassium chromate during the PC reduction process. The results showed that the film catalysts were composed of anatase and rutile TiO2 with a micro-porous surface structure. The calcination treatment increased the content of TiO2 in the film, changed the relative ratio of anatase and rutile TiO2, and decreased the size of the micro pores of the film catalysts. The removal rate of potassium chromate was related to the technique parameters of calcination/acid-activation treatment. When the anodic oxidation TiO2/Ti film catalyst was calcined at 873 K for 30 min and then acid-activated in the concentrated H2SO4 for 60 min, it presented the highest catalytic property, with the removal rate of potassium chromate of 96.3% during the PC reduction process under the experimental conditions.

A Comparative Study of Transesterification of Hydnocapus weightiana Seed Oil Using Calcined and Acid Activated Natural Heterogeneous Catalyst and Its Kinetic Study

The world’s total fossil fuel consumption has been significantly increasing with consequential increased environmental catastrophes. A hunt for an alternate energy source was stimulated. Biofuel is a plausible option in this pursuit due to its ideal qualities which included but are not limited to renewability and environmental friendliness. However, the pump price of biodiesel is still very high due mainly to the high cost of the production of the commodity which is influenced by the feedstock and the homogeneous nature of catalyst used. Heterogeneous catalyst was prepared by using Pila globosa sea snail shells prepared by calcination (CP8) and by acid activation (PTW1M). Hydnocapus weightiana seed oil (Non-edible feedstock) was extracted using the soxhlet extraction method and was used for biofuel production with a methanol oil ratio of 3:1. Agitation speed 800, 600 rmp, reaction temperatures of 70°C, 60°C, catalyst concentration (3.00, 2.00 wt%) and reaction time (70 and 60 min) was maintained for CP8 and PTW1M respectively. The rate of the reaction followed a reversible second-order reaction rate. Re-usability accessed. From TGA analysis, the best calcination temperature was 800°C. SEM results showed improved surface morphology after calcination, especially for CP8. FTIR analysis showed the elimination of volatiles and formation of CaO and CaO4Te after calcination. The reaction rate constant at different temperatures was 0.0287 at 30°C, 0.1200 at 50°C and 0.1142 at 70°C and activation energy of the ethyl ester was 49.49 KJ/mol. Using CP8. Most of the fuel properties met with ASTM 6751 standard. The result of the re-usability showed that the biodiesel yield declined as follows: 92, 86, 80, 73 and 69 % for CP8 and 85, 84, 81, 76, 65. For PTW1M. After the fifth regeneration cycle, both CP8 and PTW1M samples of Pila globosa sea snail shell catalyst proved effective in transesterification reaction of Hydnocapus weightiana seed oil using ethanol. It was observed that the calcined catalyst (CP8) showed a superior catalytic performance.

Characterization, Acid Activation and Bleaching Performance of Bentonite from Xinjiang

Bentonite produced in Xiazijie, Xinjiang (China) was characterized by X-ray diffraction (XRD), dif- ferential thermal analysis (DTA), thermogravimetric analysis (TG) and cation exchange capacity (CEC). The ben- tonite is composed of dioctahedral montmorillonite with predominant quantity, certain amounts of quartz, feldspar and illite and minor amounts of kaolinite, gypsum, etc. The raw bentonite has a CEC of 0.6497 meq·g-1 and allows to be characterized as typical sodium bentonite. In order to bleach cottonseed oil, optimum conditions for sulfuric acid activation of the raw bentonites were investigated, which were obtained by selecting various acid strength, at 96—98℃ and activating for 4h with 1︰2 solid-liquid ratio. The acid activation bentonites were suitable for decol- orization of cottonseed oil through removing carotene and chlorophyll. The bleaching capabilities of different pig- ments with activated bentonite with treatment of 25% sulfuric acid were 70.3%, 73.1%, 83.2%, 81.8% and 88.9%, respectively. Bleaching with acid activated bentonite gave oils lower peroxide values and acid values.