[en] The paper is focused on the influence of some inorganic modifiers on the thermal stability of the clay-inorganic intercalates. The inorganic modifiers used were NaOH and KOH. Solvent intercalation procedure was used. Clay was modified at 150, 500 and 750 degree C, separately with NaOH and KOH. TGDTA study was performed to evaluate the thermal stability of the resultant intercalates. Intercalation with NaOH and KOH performed at 150 degree C showed significant mass loss. Intercalation with NaOH performed at 500 and 750 degree C, separately showed less mass loss compared to the ones prepared at 150 degree C and hence exhibited thermal stability. In case of intercalation performed with KOH at 500 and 750 degree C separately, the mass loss was comparable to the original pre-baked clay. (author)

[en] Removal of Cu (II) ions from aqueous solution by sawdust of wood was investigated as function of time, pH, adsorbent concentration, adsorbent concentration and temperature. The amount of Cu (II) ions adsorbed onto sawdust increased with the increase in reaction time, concentration and temperature. Kinetic studies showed that adsorption process followed first order kinetic model. Langmuir and Freunds equations were applied to the observed data, which showed that Cu(II) ions adsorption obeys both Langmuir and Freundlich isotherms. Thermodynamics parameters such as del H, del S and del G were also estimated which suggested that the adsorption of Cu (II) ions on sawdust of wood was an endothermic and spontaneous process. (author)

[en] Lakhra coal was leached with various extractants/leachants such as HCl, H/sub 2/O/sub 2/ and KMnO/sub 4/, for the generation of porosity as well active site for the removal of maleic acid from aqueous solution. The physicochemical analyses indicated that the quantity of ash content, total sulfur and chlorine was decreased after leaching with these leachants. The adsorption study showed that the KMnO/sub 4/ treated coal sample adsorbed high quantity of maleic acid (49 mg/g) compared to H/sub 2/O/sub 2/ and HCl treated coal sample. The adsorption of maleic acid was level off after 1 h in the case of KMnO/sub 4/ treated coal while its adsorption on H/sub 2/O/sub 2/ and HCl treated coal samples increased gradually and then level off after 2 and respectively. (author)

[en] The adsorption of Murexide from aqueous solution onto the Pomegranate bark was investigated at room temperature. The morphological study presented that the HNO/sub 3/ treatment increased the surface roughness of the adsorbent. EDX studies show that the untreated Pomegranate bark had carbon content (52 wt %) and oxygen content (44 wt %) while in the case of HNO/sub 3/ treated pomegranate bark, the carbon quantity decreased (42 wt %) and oxygen quantity (52 wt %) increased. The results showed that the adsorption of Murexide dye from aqueous solution was increased as increased the adsorption time and then equilibrium was reached after 30 min of adsorption time. The HNO/sub 3/ treated Pomegranate bark adsorbed high quantity of Murexide (1.7 mg/g) as compared to untreated Pomegranate bark (0.73 mg/g), which might be due to increased surface roughness. The adsorption of Murexide was also studied at different pH, which presented that low pH was favorable for the removal of color material from aqueous solution. (author)

[en] Polyethylene Oxide (PEO) and Nanoclay/ Polyethylene Oxide nonocomposite films were prepared by solution casting technique. To know about the morphology, scanning electron microscopy (SEM) was performed which indicated that the Nanoclay was dispersed and embedded well within the polymer matrix. The polarized optical micrographs (POM) study of pure PEO showed considerable size of distinct crystalline spherulites. The size of spherulites was decreased by the incorporation of Nanoclay into the polymer matrix. It might be due to the nucleation effect of Nanoclay in Nanoclay/PEO composite which might result small size spherulites. The differential thermal calorimetry (DSC) thermograms presented that the melting temperature (T/sub m/) of pure PEO is about 65 degree C while the (T/sub m/) peak of the nanocomposites were shifted towards slightly lower temperature. It was also observed that the mechanical properties (stress and young's modulus) of the Nanoclay/PEO nanocomposites were higher than pure PEO. The thermal stability of the Nanoclay/PEO composite was shifted towards higher temperature (about 25 degree C higher than pure PEO) by the incorporation of 1 wt. % Nanoclay into the PEO matrix. (author)

[en] Surface acidity of virgin coal (Lakra Sindh, Pakistan) and variously extracted/leached coal samples with HNO/sub 3/ NaOH, and KMnO/sub 4/, were investigated by aqueous potentiometric titration employing KOH as a titrant. The titration curve of virgin coal showed that its surface might contain carboxylic, carbonyl, phenolic and other weak acidic functional groups such as enols and C-H bond. The titration curves of leached coal samples showed inflections at pH 4-11, being not similar the inflections of carboxylic groups. This inflection might be given by functional groups like CO/sub 2/, phenolic, enols and C-H. Mineral matter such as Fe, K, Zn, Mn and Ni were determined in the ash of coal by atomic absorption spectrophotometer and was found that Fe (3104 micro g/g) in the highest and Ni (36.05 micro g/g) in the lowest quantity is present in virgin coal sample. (author)

[en] The sulfur compounds in petroleum is of growing concern all over the world, because these are responsible for corrosion problems in storage, processing transportation and even most important, the quality of the fuel products. Typical problems, caused by sulfur compounds are catalyst poisoning and deactivation in down stream processing, corrosion of equipment and the oxidation of sulfur compounds to SO/sub x/ during fuels combustion, which cause serious environmental pollution. To produce fuels satisfying the new environmental legislations concerning sulfur levels, refineries need to consider desulfurization of streams that are used as fuel products. In this article information about sulfur removal technologies has been presented for petroleum-based oils. (author)