Modified desilicated natural zeolite as catalyst for Knoevenagel reaction

Natural zeolite (NaZ) has wide range of usage in agriculture and waste water treatment. However, its application as catalyst has not been widely studied. In this research, natural zeolite was modified its property and applied as base catalyst in the Knoevenagel reaction. The modification was done by desilication in alkaline solution at different temperature followed by ion exchanged with calcium and barium ions of alkaline earth metal. The natural zeolite obtained characterized with XRD showed that desilication results in lowering crystallinity of zeolite crystal while FT-IR showed Si/Al ration of the zeolite framework decrease showing the increase of Al in the framework. The catalyst produced was then tested in Knoevenagel reaction and analyzed by gas chromatography (GC) which showed that barium exchanged desilicated NaZ is more active and highly selective than calcium exchanged NaZ due to its higher basicity

Column study of humic acid removal from water into surfactant granular zeolite

In this study, natural zeolite (mordenite) was modified by using dimetliyldioctadecylammonium bromide (DDAB) with polyvinyl alcohol (PVA) to afford surfactant modified granular zeolite (SMGZ) as adsorbent for humic acid (HA) removal. Column adsorption studies were carried out to examine the optimum conditions for the removal of HA by SMGZ. The optimum loading of surfactant was later utilized in characterization studies. The SMGZ were characterized by XRD. FTIR. BET specific surface area and FESEM. The removal of HA was performed in a fixed bed reactor. The effects of different experimental parameters such as DDAB loading levels, solution pH and HA solution flow rate were evaluated. Samples were collected and analyzed using UV. The results indicated that SMGZ showed great enhanced adsorption capacity of HA compared to natural granular zeolite due to the hydrophobic interaction and hydrogen bonding. The equilibrium uptake (geq(exp)) of HA decreased with increasing, flow rate and granular size. Total removal percent (Y) of HA SMGZ was found to increase with increasing solution pH. influent concentration and bed depth

Studies on the activity of phosphotungstic acid (HPW) supported on porous kaolin and effects on the catalytic activity

Kaolin is an abundant clay mineral and chemically natural hydrous aluminosilicate with the 1:1 type layered structure. In this work mesoporous material derived from raw kaolin was obtained using starch as organic template. The surface area of the kaolin derived porous clay heterostructure (PCH) has increased remarkably from 15 to 756 m2g-1 with pore volume of 0.65cm3g-1. The FTIR spectra after pyridine adsorption showed that both raw kaolin and PCH was synthesized by a wet impregnation method. HPW incorporated into PCH significantly increased the surface acidity by forming mainly Bronsted acidities in acylation of anisole is demonstrated by varying the amount of Lewis and Bronsted acid sites

Potential contribution of low cost materials in clean technology

As the world's population approaches more than 9 billion, the strain on the planet's resources is steadily increasing. This demand can only be met by improving production methods to reduce the use of chemicals and the amount of chemical waste. Zeolites are among the least-known products for environmental pollution control, separation science and technology. This study investigates whether the use of geological sources as low-cost materials are suitable for zeolite synthesis and future applications. In this investigation natural montmorillonite clay, locally available in Erbil-Kurdistan, was used as raw material. The experiments were carried out in the presence of ultrasound 30KHz at 60°C and for different crystallization times (5, 10 &15 hours) and the results were compared with those obtained by performing conventional alkaline hydrothermal static syntheses under similar conditions and crystallization time of (90 hours). The raw material as well as the products was analyzed using; Fourier Transform Infra-Red (FT-IR), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) spectroscopy and scanning electron microscope (SEM). The experimental data were ascertained the formation of Zeolite successfully. Crystallization by ultrasound has been demonstrated to offer the possibilities of increasing the nucleation and crystallization rates of zeolites, improving the yield and directing the synthesis towards different crystal phases

University Technology Malaysia From the SelectedWorks of Hadi Nur 2008 Structural Characterization of Tungsten Oxides Supported on Titanium Silicalite

49 AbstractTitanium silicalite (TS-1) is known as an active material catalyst in the epoxidation reaction. In this study, tungsten oxides (WO 3 ) with various loading amount have been supported on the TS-1 to increase of the catalytic activity of the TS-1 material. The solids structure and property were investigated by X-ray diffraction (XRD), temperature programmed reduction (TPR), ultra violet-visible diffuse reflectance (UV-Vis-DR) and infrared (IR) spectroscopy and scanning electron microscopy (SEM) techniques. The results showed that the structure of TS-1 is not collapsed after impregnation of WO 3 . It was also found that tungsten species have interacted with the silanol groups on the surface of TS-1

Optimal conditions for the immobilization of lipase in nanosilica kit-6 matrix

The current demands of the world’s biotechnological industries are enhancement of enzyme productivity and development of novel techniques for increasing their shelf life to facilitate large scale and economic formulation. Immobilization of lipase by adsorption onto solids surfaces such as polymers1, silica2 and clay3 led to improved performance of the enzyme. This paper reported on lipase from candida rugosa immobilized in nanosilica KIT-6, in which the unique properties of KIT-6 including high surface areas, modifiable surface, and tunable pore sizes were utilized to improve the enzyme activity in hydrolysis of olive oil. The immobilization of lipase in the KIT-6 matrix was found to generate synergistic effects that enhanced enzyme stability, improved product selectivity, and facilitated separation and enzyme reuse. Lipase immobilization onto KIT-6 was optimized by varying synthesis parameters such as temperature (4-60 °C), pH (4-9 pH) and solid-liquid ratio of the enzyme solutions (0.03-0.5). The optimal immobilization conditions were pH 7.0 at 37°C and solid to liquid ratio 0.2 (v/v). Based on the enzyme activity, the immobilized lipase in nanosilica KIT-6 displayed higher operational stability than free lipase, including wider thermal and pH ranges

Structural, porosity and morphological changes of montmorillonite derived porous clay heterostructures prepared by the starch gel template method

Clay minerals are natural hydrous aluminosilicate and possess a layered silicate structure that can be found in a number of soils. Montmorillonite (MMT) is one of the clay minerals have a surface area of 191 m²g.¹ and has been used as a catalyst and adsorbent. However, their efficient use is limited due to low thermal stability and lack of porosity1-3. In this work, mesoporous materials derived from raw MMTwere obtained using the starch gel template method. Porous heterostructures (PCHs) were prepared by intercalation of cationic potato starch and hydrolysed potato starch as template, dodecylamine as co-template and tetraethylorthosilicate (TEOS) as silica pillar into the interlayer space of MMT. The effects of starch loading and aging temperature on changes of the structure, porosity and morphology of MMT in the formation of PCHswere investigated. The MMT derived PCHswas characterized by means of XRD, N2 adsorption-desorption, pyridine adsorption, FESEM and FTIR spectroscopy. The XRD and FESEM analyses of the PCHs prepared using cationic and hydrolyzed starchshowed a significant disordering of the MMT layer arrangement after treatment with the starch gel template. However, results of the nitrogen adsorption measurement showed the surface area has increased remarkably as high as 1000 m²g.¹ with average pore diameters of 3.4 – 3.8 nm and pore volumesof 0.70 to 0.87 cm3g-1. Furthermore, the structural integrity of PCHs deteriorated slightly with increasing temperature but the porosity was maintained until up to 900 .C. The FTIR spectra after pyridine adsorption showed thatboth raw MMT and PCHspossessed mainly strong Lewis acid sites. The acidity properties and high surface area of PCHsmake them useful as potential heterogeneous catalyst for the transformation of bulky organics

Phase Transformation of Rice Husk Ash in the Synthesis of ZSM-5 without Organic Template

Phase transformation of rice husk ash in the synthesis of ZSM-5 without organic template at various crystallization times has been studied. Zeolite has been synthesized using the hydrothermal method at 175 °C with molar ratio 10Na2O : 100SiO2 : 2Al2O3 : 1800H2O with addition of silicalite-1 as seed. Solids were characterized using X-ray diffraction (XRD), infrared (IR) spectroscopy and scanning electron microscopy (SEM) techniques. Analysis of the results of XRD and IR spectroscopy indicated that ZSM-5 crystalstarted to form at 12 h of crystallization time, reaching high crystallinity after 24 h. With a crystallization time of more than 48 h, the ZSM-5 crystals had completely transformed into more stable quartz phase. Results indicated that phase transformation has occurred, in which an amorphous phase of rice husk ash has been transformed to ZSM-5 crystal phase during the early crystallization stage and continued to transform to disordered α-cristobalite phase and lastly quartz phases. SEM showed that the morphology of the ZSM-5 crystal was of an irregular hexagonal shape with particle size distribution around 3-7 μm

Electrochemical performance of ordered mesoporous carbon modified by oxidative treatment with aqueous nitric acid

In this study, ordered mesoporous carbon (OMC) was prepared via nano-casting method by using Santa Barbara Amorphous (SBA)-15 as a template and sucrose as a carbon precursor. The OMC was subsequently oxidized with aqueous nitric acid and referred as MOMC. The physicochemical properties of OMC and MOMC were determined using nitrogen adsorption–desorption analyser, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). The results proved that the carbon replication process was successful. The electrochemical performance tests were carried out using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) in 1 M KOH electrolyte for 1000 cycles. After oxidative treatment, the specific surface area and pore volume of OMC decreased but the specific capacitance of the electrode material has significantly increased from 117 F g–1 to 344 F g–1 at a scan rate of 10 mV s–1

New dispersive solid phase miroextraction sorbent based on so-gel bybrid material for non-sterioidal anti- inflammatory drug analyis in water

Dispersive solid phase microextraction (DSPME) is a simple and environmental friendly sample preparation technique. In DSPME, the sorbent is used for trapping the analyte/s out of the solution and then the analyte/s is to a smaller volume of a second desorption solvent. In this study, a new DSPME sorbent material based on a hybrid organic–inorganic methyltrimethoxysilane–cyanopropyltriethoxysilane (MTMOS–CNPrTEOS) was synthesized by using two steps sol–gel method. The new DSPME hybrid sorbent was used in determination of three selected NSAIDs namely, diclofenac sodium, ketoprofen and mefenamic acid in water samples prior to high performance liquid chromatography with ultraviolet (HPLC-UV) detection. Under the optimized conditions, the method demonstrated good linearity (0.2–500 µg L-1) with excellent coefficient of determination (r2 > 0.9991), good RSDs (<2.4%, n = 3), good limit of detection (0.03–0.12 µg L-1) and excellent recoveries (93.5–97.6%). The DSPME method using the new sol-gel hybrid MTMOS–CNPrTEOS material combined with HPLC–UV proved to be a simple, cost efficient and requires minimial amount of organic solvent that support green chemistry concepts