Topic
Activated alumina
About: Activated alumina is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 31090 citations.
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01 Dec 2019TL;DR: In this article, the authors used three adsorbents viz. activated alumina and activated carbon from coconut coir and rice husk ash to study the phenol removal efficiency using several isotherms and kinetic and thermodynamic models.
Abstract: Phenol (C6H5OH) is considered as a serious environmental pollutant, and therefore, the study for its removal from wastewater by adsorption has gained momentum by many researchers. The purpose of this research was to study the phenol removal efficiency using three adsorbents viz. activated alumina and activated carbon from coconut coir and rice husk ash. Initially, the characterizations of the adsorbents were performed. The phenol removal percentage was then investigated in batch experiments with the change of process variables, e.g., initial phenol concentration, contact time, pH, temperature, and adsorbent dose. The experimental results showed that at optimum conditions, the maximum phenol removals for activated alumina and activated carbon from coconut coir and rice husk ash were 21.8%, 95.2%, and 94.23% respectively. These results were tested using several isotherms and kinetic and thermodynamic models. The test of kinetic models showed that pseudo-second-order model was fitted better than the pseudo-first-order model for all three adsorbents. The test of isotherm models showed that the Freundlich isotherm was better for activated alumina and activated carbon from coconut coir, whereas the Langmuir isotherm was better for rice husk ash. The thermodynamic study showed that the adsorption process was non-spontaneous, non-random, and exothermic for activated alumina; spontaneous, non-random, and exothermic for activated carbon from coconut coir; and spontaneous, random, and endothermic for rice husk ash. The safe disposals of the spent adsorbents were also deliberated in this study. The research discovered that the preference of adsorbents for phenol removal was rice husk ash, activated carbon from coconut coir, and activated alumina. The novelty of this study was that the paper had included exhaustive analysis using testing of numerous models viz. pseudo-first-order model, pseudo-second-order model, Reichenberg model, Fick model, Furusawa and Smith model, Elovich model, Boyd model, Langmuir model, Freundlich model, Temkin model, and Dubinin–Radushkevich model.
9 citations
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10 Feb 1975
TL;DR: In this article, the authors used activated alumina with sodium permanganate and a basic sodium compound to reduce nitrogen oxides in the smoke obtained from the tobacco product after the filter material is stored for long periods of time in the presence of volatile components of the tobacco products and/or moisture.
Abstract: Novel compositions are prepared by impregnating activated alumina with sodium permanganate and a basic sodium compound. When used as a granular filter material in combination with a tobacco product as in a smoking article comprising a cigarette in combination with the filter materials, nitrogen oxides can be significantly reduced in the smoke obtained from the tobacco product after the filter material is stored for long periods of time in the presence of the volatile components of the tobacco product and/or moisture. Activated carbon may also be combined with the composition.
9 citations
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11 Aug 1979
TL;DR: In this article, a three-way catalyst for cleaning exhaust gas from internal cumbustion engine, an activated alumina of an ignition loss of 5-20%, obtained by quickly dehydrating aluminium hydroxide in a high-temperature gas, is mixed with cerium oxide or cerium hydroxides in an amount of 10-18% (as CeO2 of a purity of 90% or more), granulated, cured in a saturated steam, dried, and then baked at 800-1,100 deg.
Abstract: PURPOSE:To manufacture a CeO2-containing catalyst having an oxygen storing effect, by a procedure in which activated alumina obtained by quickly dehydrating aluminium hydroxide is mixed with cerium oxide, granulated, cured, and then baked to obtain a three-way catalyst. CONSTITUTION:As a three-way catalyst for cleaning exhaust gas from internal cumbustion engine, an activated alumina of an ignition loss of 5-20%, obtained by quickly dehydrating aluminium hydroxide in a high-temperature gas, is mixed with cerium oxide or cerium hydroxide in an amount of 10-18% (as CeO2 of a purity of 90% or more), granulated, cured in a saturated steam, dried, and then baked at 800-1,100 deg.C. The catalyst thus obtained, containing CeO2 having an oxygen storing effect,can clean NOx, CO, and hydrocarbons effectively and concurrently.
9 citations
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25 Jul 1960
TL;DR: In this article, a mixture of ethyl mercaptan and diethyl sulphide is obtained by reacting hydrogen sulphide with ethylene in the presence of a catalyst consisting of alumina or silica containing 0.1% to 10% by weight of heteropoly acid or an alkali metal or alkaline earth metal salt thereof.
Abstract: A catalyst comprises alumina or silica promoted with a heteropolyacid or an alkali metal or alkaline earth metal salt of such acid. The acid may contain molybdenum or tungsten together with boron, silicon, germanium, titanium, zirconium, thorium, phosphorus, vanadium, arsenic or manganese. The alumina or silica is impregnated with an aqueous solution of the acid or salt and dried to give a catalyst containing from 0,1 to 10% by weight of the promoter. In examples the catalysts specified are phosphotungstic acid on activated alumina, silicotungstic acid on alumina, phosphotogungstic acid on activated silica, and potassium phosphotungstate on alumina. The catalyst may be used in a fixed or fluidized bed reactor.ALSO:Ethyl mercaptan and diethyl sulphide are obtained by reacting hydrogen sulphide with ethylene in the presence of a catalyst consisting of alumina or silica containing 0.1% to 10% by weight of heteropoly acid or an alkali metal or alkaline earth metal salt thereof. The reaction is carried out at 250 DEG to 400 DEG C., at a pressure of at least 100 p.s.i.g., with a mole ratio of H2S:C2H4 between 1:1 and 20:1, and a space velocity of at least 25 c.c. of ethylene per hour per c.c. of catalyst. In examples mixtures of ethyl mercaptan and diethyl sulphide are obtained using as catalysts phosphotungstic acid on alumina, silicotungstic acid on alumina, phosphotungstic acid on p silica and potassium phosphotungstate on alumina. Other heteropoly acids may be used containing molybdenum or tungsten together with boron, silicon, germanium, titanium, zirconium, thorium, phosphorus, vanadium, arsenic or manganese.
9 citations
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16 Feb 1977
TL;DR: In this paper, a process for preparing o-benzylphenol in high selectivity is described, which comprises heating a mixture of benzyl alcohol and phenol in the presence of an effective amount of activated alumina as a catalyst.
Abstract: A process for preparing o-benzylphenol in high selectivity is disclosed. The process comprises heating a mixture of benzyl alcohol and phenol in the presence of an effective amount of activated alumina as a catalyst.
9 citations