Defluoridation of drinking water using chitosan based mesoporous alumina

In the present research study, mesoporous alumina (MA450) with improved properties has been synthesized using biopolymer chitosan as a template and used for defluoridation of water. The adsorbent has been characterized with XRD, SEM, FTIR and EDAX studies. It was observed that MA450 works effectively over wide range of pH and showed a maximum adsorption capacity 8.264 mg g�1 at initial fluoride concentration of 5 mg l�1 which is much better than the conventional alumina. The experimental data fitted well in Langmuir isotherm and follows Pseudo-second order kinetics. Batch adsorption studies were performed to study the effect of pH, adsorbent dose, initial fluoride concentration and co-existing anions. Thermodynamic study reveals that fluoride adsorption on MA450 is spontaneous and exothermic process. MA450 showed significantly high fluoride removal in field water. The performance of MA450 was compared with many other reported adsorbent for fluoride removal and it was observed that the present adsorbent is effective in terms of fluoride removal performance and also appears to be cost effective. From the experimental data, it may be inferred that MA450 is a potential and indigenous adsorbent for defluoridation

Combustion of volatile organic compounds over Cu–Mn based mixed oxide type catalysts supported on mesoporous Al2O3, TiO2 and ZrO2

A series of supported Cu–Mn based catalysts have been synthesized using three different supports mesoporous Al2O3, mesoporous TiO2 and mesoporous ZrO2. Cu–Mn precursors were incorporated on mesoporous supports using wet impregnation method. These catalyst supports were prepared by templating method using a natural biopolymer namely, chitosan. The catalytic activity for benzene and acetaldehyde combustion was studied for these catalysts. The synthesized catalysts have been characterized by XRD, BET-SA, O2-TPD and H2-TPR in a view of material characterization, as well as to investigate the mechanistic aspects of catalytic reactions. The bimetallic supported catalysts follow the activity sequence—Cu–Mn/TiO2 > Cu–Mn/ZrO2 > Cu–Mn/Al2O3 for both the reactions studied. These results interestingly show, that the catalytic activity is dependent on the support used, however, quite independent of the surface area of these supports. The better activity of TiO2 and ZrO2 based catalysts is likely due to their redox properties. The existence of low temperature peaks in both O2-TPD and H2-TPR explain better redox properties as well as catalytic performance of TiO2 and ZrO2 supported catalysts as compared to those Al2O3 supported mixed oxides

Catalytic Control Options for Diesel Particulate Emissions Including that from Locomotive Engines

Diesel engines have gained an edge over other fuel engines in heavy duty transportation sector owing to their high efficiency, high durability and reliability with low operational costs. Also, in the last few decades, diesel engines have chunked out a growing share in the light-duty vehicle market as well

Thermally stable metal ruthenate based soot oxidation catalyst for diesel exhaust emission control

Lanthanum ruthenate materials with perovskite type structure can be easily synthesized with ruthenium in 4+ oxidation state. La3.5Ru4.0O13 type perovskite has been synthesized in unsupported and supported forms by using various methods. This perovskite type La3.5Ru4.0O13 phase shows high thermal stability and can therefore be used as a catalyst for high temperature applications, including those for auto-exhaust emission control. The material shows good catalytic activity for the carbon/soot oxidation in view of its possible application in diesel soot oxidation for regeneration of Diesel Particulate Filter

Adsorption of fluoride from aqueous solution by alumina of alkoxide nature: batch and continuous operation

In this investigation, we report the adsorption potential of alkoxide origin alumina for defluoridation of drinking water using batch and continuous mode of operations. The effects of different operating parameters such as adsorbent dose, initial fluoride concentration, pH of the solution and interfering ions (usually present in groundwater) were studied with a view to understand the adsorption behavior of the material under various conditions. A thermodynamic study shows that the adsorption of fluoride by alkoxide origin alumina is an exothermic and spontaneous process. The kinetic results showed that the fluoride sorption follows pseudo-second-order kinetics. The applicability of adsorbent in the field is also tested through column breakthrough studies. It has been observed that with an increase in the flow rate and initial fluoride concentration, the breakthrough curve becomes sharper and the breakthrough time and adsorbed fluoride ion concentration decrease. The breakthrough curve also becomes steeper as the bed height increases. The alkoxide origin alumina based adsorbent media can be used directly for field applications since it is also commercially available in granular form

Coal and Biomass based Fuels in Rural India : Emissions and Possibility of their Control

Papers reported in the 7th International Symposium on \u22Novel Carbon Resource Sciences\u22 Jun. 23-24, 2011Emissions from solid fuels used in the rural areas have been recognized as a major environmental and health hazard in India and many other developing countries. Use of these fuels is expected to continue in near future, and it is necessary to find techno-economically feasible solutions for emission control. Monitoring of CO and PM emissions as well as temperature measurements for rural cook-stoves have been done at actual emission sources, for some common solid fuels used in India. Based on these data, a catalytic approach for emission control from rural cook-stove has been explored by study of catalytic materials for CO oxidation

Amine loaded zeolites for carbon dioxide capture: Amine loading and adsorption studies

Novel functionalised adsorbents have been synthesized by immobilization of various amines on synthetic zeolite 13X. Various primary and secondary amines namely monoethanolamine (MEA), ethylenediamine (ED) and isopropanol amine (IPA) have been immobilized on zeolite 13X. Quantitative estimations of the amine loadings were undertaken using different analytical techniques namely titrimetric, total organic carbon and gas chromatography analysis. Fairly good correlation was obtained for amine loadings estimated using the three techniques. Effect of various parameters like effect of solvent, shaking time, synthesis temperature, and wetting of pellets prior to amine loadings was also studied. The results revealed that maximum loading was achieved for methanol-mediated synthesis conducted using previously wetted pellets at room temperature and with 15 min of shaking time. Preliminary attempts have also been made to determine the CO2 adsorption capacities of these newly developed materials. The adsorption capacities obtained were 16.01 mg/g for unmodified zeolite 13X and 19.98, and 22.78 mg/g for zeolite modified with monoethanol amine, and isopropanol amine

Alumina Supported Co–K–Mo Based Catalytic Material for Diesel Soot Oxidation

Alumina supported Co–K–Mo based mixed metal oxide type catalytic materials have been prepared by co-impregnation. These catalysts show excellent activity for carbon as well as diesel soot oxidation, which could be due to the redox properties of Mo and Co as well as to a synergistic effect of molybdenum, cobalt, and K contents. The catalyst containing 5 wt% molybdenum shows a lowering of carbon oxidation by about 190 °C under loose contact conditions as compared to the non-catalyzed reaction, as well as to bare alumina. Characterization studies suggest a composite nature of these materials, while thermal stability investigations confirm the stable nature. The selected catalyst has been studied by XPS, however, it is difficult to conclude which are the important factors contributing to the catalytic activity. It appears to be a synergistic effect of Co, K, and Mo components as these catalysts show much improved activity as compared to the individual components in supported and unsupported forms

Coal and Biomass based Fuels in Rural India : Emissions and Possibility of their Control

Emissions from solid fuels used in the rural areas have been recognized as a major environmental and health hazard in India and many other developing countries. Use of these fuels is expected to continue in near future, and it is necessary to find techno-economically feasible solutions for emission control. Monitoring of CO and PM emissions as well as temperature measurements for rural cook-stoves have been done at actual emission sources, for some common solid fuels used in India. Based on these data, a catalytic approach for emission control from rural cook-stove has been explored by study of catalytic materials for CO oxidation.Papers reported in the 7th International Symposium on "Novel Carbon Resource Sciences" Jun. 23-24, 201

Ceria Supported Pt/PtO-Nanostructures: Efficient Photocatalyst for Sacrificial Donor Assisted Hydrogen Generation under Visible-NIR Light Irradiation

In photocatalysis, imperative photoredox behavior and narrow band gap are important properties to exploit solar light for water splitting reaction. Nanostructured ceria (cerium dioxide/CeO₂) with Ce³⁺/Ce⁴⁺ (photoredox couple) shows significant enhancement in photocatalytic activity, however, no significant activity for water splitting reaction. The present study mainly focuses on incorporation of Pt on nanostructured mesoporous ceria by wet-impregnation method and its evaluation for donor assisted photocatalytic water splitting reaction. The BET analysis shows much higher surface area (119–131 m² g^–1) for unmodified as well as Pt modified mesoceria samples as compared to commercial ceria (24.4 m² g^–1), although structure was not ordered. The incorporation of Pt on mesoceria shows remarkable influence on photocatalytic hydrogen generation activity, and 1 wt % Pt was found to be optimized content, with broader light absorption. This photocatalyst was optimized with respect to photocatalyst dose, use of different sacrificial donors and their concentrations as well as other experimental parameters, with 34 h time course evaluation, yielding cumulative 1.52 mmol of hydrogen, under visible-NIR light irradiation and using ethanol as a sacrificial donor. The XPS, BET and photoluminescence studies imply that the enhanced photocatalytic hydrogen evolution in the case of mesoceria is due to the unison of high surface area, reduced recombination of photogenerated charge carrier and lower Ce³⁺ concentration in the case of mesoceria