A series of Ptl-xC~x/A1203 bimetallic catalysts have been characterized by temperature-programmed reduction (TPR), chemisorption of hydrogen and CO, deuterium exchange using both methanol and methane, and activity for the CO/H2 reaction. A Pt-assisted reduction mechanism over the entire range of composition was established by the TPR studies as well as by the chemisorption results. An enhanced metallic dispersion for the Pt-rich catalyst and formation of bimetallic particles on the Co-rich side was also indicated. In the CO hydrogenation over the Pt-rich catalysts the predominant products are methanol and dimethyl ether whereas on the Co-rich samples hydrocarbons and higher alcohols are produced. The mechanisms of deuterium exchange with methane and methanol are significantly different, the former being catalyzed solely by metallic sites while the latter utilizes both oxide and metallic sites for stepwise and multiple exchange, respectively. On the basis of the XPS data (preceding article) as well as the chemisorption results reported here, a surface model is introduced for interpretation of the catalytic results. IntroductionThe increasing production of methanol has initiated considerable effort in finding new routes for expanding its utilization. Research has been done on the use of methanol in phenol alkylation' and in the low-temperature route for methanol formation from carbon monoxide using methyl formate in the homogeneous phase,2 and methanol can also be a starting compound for production of specialty chemicals such as methyl a~e t a t e .~ In all these processes methanol must be activated; thus, information about its interaction with catalysts becomes of primary interest. Furthermore, this interaction could attract great attention also in fundamental catalysis, because in methanol there are three

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Natural indigo is hardly used anymore, replaced by synthetic indigo. Considered to be more powerful and more intense. The aim of this study is to optimize the method of extracting indigo carmine from the Isatis plant located in the Timhdit region of Morocco, during the fermentation period of the extracted liquid (pH = 10) and by adding 10% sugar it was possible to increase the yield by 0.5% indigo carmine blue powder to 0.9%. The main effect of applying centrifugation at 7000 rpm instead of conventional filtration is the reduction of the time from 30 min to 5 min as well as the reduction of the loss of traces of indigo in the filter papers by easily recovering the blue powder in the form of sediment in the centrifuge tubes. The extracted pigment is characterized by the infrared which confirmed the structure of the indigo carmine obtained, by visible UV spectroscopy, the maximum absorption of which is approximately 598 nm. This blue pigment was applied to the wool fibres by optimizing the dyeing procedure (T = 50 ° C and pH=10) with a 1/100 bath ratio and a 35 min soaking time. Dyed wool sample has reached a rigid fixation confirmed by the test for fastness washing 105-C06 and to friction 105 -X12.

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In this work, olive mill wastewater (OMW) such as dyes is very toxic even present as traces in industrial wastewater effluents. It may constitute a potential pollution source of ground waters and hence it has to be eliminated. Various low cost adsorbents have been studied for their applicability in treatment of different types of effluents. In this study, the potential of activated carbon derived from Olive Stones was studied for the removal of OMW. The biosorption of OMW from aqueous solutions by Olive Stones (OLS) as a low-cost, natural and eco-friendly biosorbent was investigated and by KOH and H3PO4 treated Olive Stones (AOLS). Biosorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherm data were analyzed using Langmuir, Freundlich isotherm equations. The best fit was obtained by the Langmuir model with a Langmuir maximum monolayer biosorption capacity of 189,83 mg/g for OMW. The biosorption was exothermic in nature (H° = -105,54 kJ/mol). The reaction was accompanied by a decrease in entropy. The Gibbs energy (G°) increased when the temperature was increased from 303 to 320 °K indicating a decrease in feasibility of biosorption at higher temperatures. The results have established good potentiality for the Olive Stones to be used as a sorbent for the removal of olive mill wastewater.