• A Novel Method for Cleaning Reaction Vessels.

      Cox, Jeffrey J.; Gibbons, M. N. N.; Hudson, I. D.; Williams, Craig D. (NISCAIR, 2002)
      The objective of zeolite synthesis is the production of pure phase material and a study by Lowe et al. showed that small and possibly significant amounts of template remaining in supposedly clean vessels could influence the crystallisation of subsequent gels. Two cleaning methods are widely used to clean the synthesis reaction vessels i.e. hydrofluoric acid or a solution of sodium hydroxide at reaction temperature, but their efficacy has not been tested. Zeolite omega was synthesized with both organic and inorganic templates and, following synthesis, the reaction vessels were cleaned by a novel method, described here, using hydrofluoric acid, crown ethers, and ultrapure water. This new method was compared to the standard methods by using a ‘scavenging gel’ to test the cleanliness of the vessels. The ‘scavenging gel’ produced some crystalline material when used following conventional cleaning whereas, when the vessels were cleaned using the method described here, the gel failed to crystallise. Conductivity measurements have proved a reliable index to the cleanliness of the reaction vessels.
    • A study of the chemistry of isomorphous substitution and characterisation of Al-ZSM-5 and Sc-ZSM-5 synthesised in fluoride media.

      Brigden, Clive T.; Williams, Craig D.; Apperley, David C. (MAIK Nauka/Interperiodica distributed exclusively by SpringerLink, 2007)
      Al-ZSM-5 and Sc-ZSM-5 samples have been synthesized using fluoride media at around neutral pH. The synthesis chemistry has been studied and it is shown how the lower tendency of scandium to undergo increased fluoro-complexation (compared with aluminum) coupled with its tendency to hydrolyze is conductive to its isomorphous substitution and framework incorporation into the MFI zeolite structure. Clear unit cell volume expansion, elongation of the c crystallographic axis with increased scandium content, and a strong positive linear correlation between the unit cell volume expansion and the calculated unit cell framework scandium content are shown. Chemical shifts are assigned to tetrahedral and octahedral scandium from 45Sc MAS NMR analysis. Shoulders and a peak at lower wavenumber on the main internal T-O asymmetric stretches in the FT-IR spectra indicate that an interaction exists between framework-incorporated scandium and the SiO4 tetrahedra. It is concluded from the experimental evidence that isomorphous substitution of scandium into the zeolite framework has been achieved.
    • Bacterial synthesis of biodegradable polyhydroxyalkanoates.

      Verlinden, Rob A. J.; Hill, David J.; Kenward, M.A.; Williams, Craig D.; Radecka, Izabela (Wiley InterScience, 2007)
      Various bacterial species accumulate intracellular polyhydroxyalkanoates (PHAs) granules as energy and carbon reserves inside their cells. PHAs are biodegradable, environmentally friendly and biocompatible thermoplastics. Varying in toughness and flexibility, depending on their formulation, they can be used in various ways similar to many nonbiodegradable petrochemical plastics currently in use. They can be used either in pure form or as additives to oil-derived plastics such as polyethylene. However, these bioplastics are currently far more expensive than petrochemically based plastics and are therefore used mostly in applications that conventional plastics cannot perform, such as medical applications. PHAs are immunologically inert and are only slowly degraded in human tissue, which means they can be used as devices inside the body. Recent research has focused on the use of alternative substrates, novel extraction methods, genetically enhanced species and mixed cultures with a view to make PHAs more commercially attractive.
    • Design, synthesis and applications of cell-penetrant peptides as signal transduction modulators

      Howl, John D.; Farquhar, Michelle; Jones, Sarah (Springer Verlag, 2006)
      THIS BOOK: Understanding Biology Using Peptides: Proceedings of the 19th American Peptide Symposium highlights many of the recent developments in peptide science, with a particular emphasis on how these advances are being applied to basic problems in biology and medicine. Specific topics covered include novel synthetic strategies, peptides in biological signaling, post-translational modifications of peptides and proteins, peptide quaternary structure in material science and disease, and peptides as tools in drug discovery. (Springer Verlag)
    • Ni-ZSM-5 and Cu-ZSM-5 Synthesized Directly from Aqueous Fluoride Gels.

      Round, Catherine I.; Williams, Craig D.; Latham, Kay; Duke, Catherine V. A. (ACS Publications, 2001)
      Ni-ZSM-5 and Cu-ZSM-5 have been synthesized in a slightly acidic fluoride medium. A low water H-ZSM-5 formula was used to synthesize the metal-substituted systems using bis(tetraethylammonium) tetrachloronickelate(II) [N(CH2CH3)4]2[NiCl4] and bis(tetraethylammonium) tetrachlorocuprate(II) [N(CH2CH3)4]2[CuCl4] as the tetrahedrally coordinated metal species. X-ray diffraction analysis established the presence of highly crystalline and thermally stable material. Unit cell dimensions increased with increasing levels of metal substitution. X-ray fluorescence (XRF) bulk analysis showed increasing levels of metals in the material and corresponding decreases in the moles of silica. The maximum levels of substitution achieved were Ni 3.93 and Cu 4.38 (in wt %). Analysis by scanning electron microscopy (SEM) showed a crystal morphology similar to that of H-ZSM-5 but with smaller crystals having an increasing aspect ratio in the substituted materials. There was evidence of twinned crystals and the appearance of raised faces in all substituted samples. Thermogravimetric and derivative thermogravimetric analysis showed anomalous losses, which could be explained by Jahn-Teller distortions. Fourier transform infrared analysis of the materials showed an increasing level of distortion in significant regions of the spectra. Analysis of the filtrate, from EDTA-exchanged material, by atomic absorbance spectroscopy (AAS) showed that there were tetrahedrally coordinated M2+ species in the material and relatively small amounts were removed by ion exchange.
    • Nucleation and growth history of zeolite LTA synthesized from kaolinite by two different methods.

      Rios, Carlos A.; Williams, Craig D.; Fullen, Michael A. (Amsterdam: Elsevier, 2009)
      The synthesis of zeolite Linde Type A (LTA) from kaolinite by two different routes: (1) conventional hydrothermal alkaline activation and (2) alkaline fusion prior to hydrothermal reaction, as well as its nucleation and growth history, were investigated. Using the first method, co-crystallization of sodalite and cancrinite, probably via an unstable zeolite LTA intermediate, was observed during treatment of kaolinite in NaOH solutions. The addition of a SiO2 source promoted the co-precipitation of several zeolite phases, including zeolites LTA, X and P, with traces of sodalite and cancrinite. By fusion with NaOH followed by hydrothermal reaction, kaolinite was converted into zeolite LTA. Synthesized materials appeared stable thermodynamically under the experimental conditions. The synthesis products have been characterized by X-ray diffraction, scanning electron microscopy and Fourier Transform Infrared Spectroscopy.
    • Parametric, equilibrium, and kinetic study of the removal of salt ions from Ghanaian seawater by adsorption onto zeolite X

      Kwakye-Awuah, Bright; Von-Kiti, Elizabeth; Nkrumah, Isaac; Erdoo Ikyreve, Rose; Radecka, Iza; Williams, C. (Taylor & Francis, 2016-01-05)
    • Peptide Synthesis and Applications

      Howl, John D. (Clifton, N.J.: Humana Press, 2005)
      Hands-on experts describe in step-by-step detail the key methodologies of contemporary peptide synthesis and illustrate their numerous applications. The techniques presented include protocols for chemical ligation, the synthesis of cyclic and phosphotyrosine-containing peptides, lipoamino acid- and sugar-conjugated peptides, and peptide purification and analyses. Additional chapters detail methodologies and instrumentation for high-throughput peptide synthesis, many different applications of peptides as novel research tools and biological probes, and the design and application of fluorescent substrate-based peptides that can be used to determine the selectivity and activity of peptidases. A practical guide to the identification of proteins using mass spectrometric analyses of peptide mixtures is also included. (Humana Press)
    • Synthesis and characterisation of aluminophosphate-based zeotype materials prepared with α,ω-bis(N-methylpyrrolidinium) alkane cations as structure directing agents.

      Maple, Martin J.; Williams, Craig D. (RSC Publishing, 2007)
      New routes to the preparation of two families of small pore microporous solids are described. Flexible diquaternary alkyl ammonium cations (C4H8)CH3N+(CH2)nN+CH3(C2H8), n = 3–5, have been found to act as structure directing agents in the synthesis of aluminophosphate-based materials of the ABC-6 group. The templates exhibit considerable selectivity in crystallising phases of the ERI or AFX-type (MeAPO-17 or MeAPO-56, respectively) from a wide variety of metalloaluminophosphate gels (Me = Mg2+, Co2+ or Si4+). For example, from gels containing Mg/P = 0–0.25, 1,4-bis(N-methylpyrrolidinium)butane cations gave MgAPO-17, and 1,5-bis(N-methylpyrrolidinium)pentane cations gave MgAPO-56. Notably, materials could be prepared with levels of metal-substitution tailored to a high degree and distributed non-randomly within the framework. As-prepared solids have been characterised by powder XRD, multinuclear solid state NMR, FT-IR, SEM, and thermal and elemental analysis.
    • Synthesis and characterization of zeotype ANA framework by hydrothermal reaction of natural clinker.

      Sandoval, M.V.; Henao, J.A.; Rios, Carlos A.; Williams, Craig D.; Apperley, David C. (Amsterdam: Elsevier, 2009)
      The zeotype ANA framework was successfully synthesized for the first time by conventional hydrothermal alkaline activation of natural clinker. The synthesis process was investigated as a function of the starting material, reaction temperature, reaction time and mineralizer concentration. The as-synthesized products were characterized by X-ray powder diffraction (XRPD) analysis, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, magic-angle spinning nuclear magnetic resonance (MAS NMR) and thermogravimetric analyses (TGA). The results of this study indicate that ANA with a low quantity of impurities can be synthesized using natural clinker as starting material.
    • Synthesis of high silicon content SAPO(4)-5 using anionic surfactants in a hexanol/aqueous two phase media.

      Han, Xue S.; Williams, Craig D.; Lee, Darren F.; Round, Catherine I. (Royal Society of Chemistry, 2002)
      High silicon content SAPO(4)-5 (up to 0.511 atoms per unit cell) has been synthesised, using sodium 3-bromopropanesulfonate, sodium 1-butanesulfonate, sodium naphthalene-1-sulfonate or sodium n-decyl sulfate as surfactants; the SiO2 in the reaction gels ranged up to 3.0 (molar ratio), silicon incorporation was confirmed by XRD, XRF, TG-DTA, FT-IR and SEM techniques.
    • Synthesis of Zeolites and Zeotypes by Hydrothermal transformation of Kaolinite and Metakaolinite.

      Rios, Carlos A.; Williams, Craig D.; Maple, Martin J. (Bucaramanga, Colombia: Universidad de Pamplona, 2007)
      The synthesis of zeolitic materials by hydrothermal transformation of kaolinite and metakaolinite in NaOH solutions of various concentrations was investigated between 100 and 200 degrees C, over different reaction times, using in some cases precipitated SiO2 or organic templates. Materials were obtained, including clathrasils: cancrinite (CAN), sodalite (SOD), and Linde Type A (LTA), faujasite (FAU), NaP1 (GIS), analcime (ANA) and nepheline hydrate I (JBW) zeolites. In general, co-crystallization of CAN and SOD, likely via an unstable LTA zeolite intermediate, was observed after dissolution of kaolinite at low temperature; although the feldspathoids tend to be unstable at high temperature. LTA zeolite was synthesized after metakaolinite reaction, with minor amount of FAU zeolite, ANA and SOD. Solids were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA).
    • Synthesis of zeolites from geological materials and industrial wastes for potential application in environmental problems

      Williams, Craig D.; Roberts, Clive L.; Fullen, Michael A.; Rios Reyes, Carlos A. (University of WolverhamptonSchool of Applied Sciences, University of Wolverhampton, 2008)
      Zeolites are among the least-known products for environmental pollution control, separation science and technology. Due to their unique porous properties, they are used in various applications in petrochemical cracking, ion-exchange and separation and removal of gases and solvents. The preparation of synthetic zeolites from chemical reagents is expensive. Therefore, in order to reduce costs, zeolite researchers are seeking cheaper aluminosilicate bearing raw materials, such as clay minerals, to produce synthetic zeolites. This research concerns the synthesis of zeolites and zeotypes derived from low-cost materials like kaolinite (KAO), natural clinker (NC) and fly ash (FA). The motivation for using these sources as the starting materials in zeolite synthesis is driven by factors, such as they are cheap and available in bulk quantities, are currently under-utilized, have high workability, and require less water (or solution) for activation. The raw materials were activated by two different routes: (1) classic alkaline hydrothermal synthesis and (2) alkaline fusion prior to hydrothermal synthesis. In the first method, the synthesis of zeolitic materials was carried out generally in alkaline media, although KAO or its calcination product, metakaolinite (MTK), was also activated in the presence or absence of structure directing agents (SDAs) and additional silica (precipitated SiO2), with the last one determining the SiO2/Al2O3 ratio of the reaction mixture and the time given for zeolitization. Synthesis in fluoride- and calcium-bearing media was also used to activate kaolinite. The process of synthesis was optimized by applying a wide range of experimental conditions with a wide range of reaction temperature, time, mineralizer concentration and solid/solution ratio. In the second approach, an alkaline fusion step was conducted prior to hydrothermal treatment, because it plays an important role in enhancing the hydrothermal conditions for zeolite synthesis. On the other hand, this approach was adopted because it can dissolve more aluminosilicates. The main synthesis products obtained after activation of KAO in NaOH solutions included zeolite LTA (LTA), sodalite (SOD), cancrinite (CAN), faujasite (FAU), zeolite Na-P1 (GIS), JBW-type zeolite (JBW), analcime (ANA), whereas the activation of KAO in KOH solutions produced chabazite (CHA), zeolite Barrer-KF, phillipsite (PHI) and K-feldspar. The hydrothermal conversion of kaolinite in fluoride media did not produce successful results, although traces of FAU, GIS, CHA, SOD and CAN crystallized. The activation of KAO in the system CaO-SiO2-Al2O3-H2O promoted the formation of different calcium silicate hydrate (C-S-H) phases, including hydrogarnet (HYD) and tobermorite (TOB). Following the fusion approach, the main zeolitic phases obtained using NaOH as mineralizer were LTA and CAN. The main as-synthesized zeolites obtained from NC by the conventional hydrothermal treatment method include PHI, SOD and CAN. Using the fusion approach, FAU and LTA were obtained with NaOH as an activator, whereas non-zeolitic material crystallized when KOH was used. The main as-synthesized zeolitic materials obtained by hydrothermal reaction of FA include PHI, zeolite Barrer-KF, CHA and SOD with traces of TOB, ANA, zeolite LTF (LTF) and herschelite (HER), appearing occasionally. By the fusion approach, FAU was obtained with NaOH as activator, whereas no zeolitic material crystallized using KOH. Experimental results indicate that the method, mineralizer, concentration and time have strong effects on the type and degree of crystallinity of the synthesis products. On the other hand, the type and chemical composition of the as-synthesized products are strongly dependent on the chemical composition of the starting material. The chemistry of zeolite synthesis was subject to perturbations caused by the presence of impurities in the raw materials, which may remain insoluble during crystallization and cause undesired species to nucleate, developing mixtures of different types of zeolites. However, other physicochemical factors may play a very important role in the thermodynamics and kinetics of zeolite formation. The raw materials have very high contents of SiO2 and Al2O3, with SiO2/Al2O3 ratios appropriate for the synthesis of low-Si zeolitic materials with high crystallinity and cation exchange capacity (CEC). However, although zeolites’ CEC represents a very important characteristic quality in the removal of undesired species from polluted effluents, it is not the deciding factor in determining zeolite performance during ion exchange processes, since numerous other factors also need to be considered. Finally, the potential application of the raw materials and their as-synthesized products as low-cost sorbents in the remediation of metal ions and ammonium from wastewater effluents was investigated. PHI showed a lower efficiency than FAU. Selectivity of FAU for metal removal was, in decreasing order, Fe>As>Pb>Zn>Cu>Ni>Cr. Based on these results, the use of these materials has the potential to provide improved methods for the treatment of contaminated effluents.
    • Synthesis of zeolitic materials from natural clinker: A new alternative for recycling coal combustion by-products.

      Rios, Carlos A.; Williams, Craig D. (Amsterdam: Elsevier, 2008)
      In this study, we report an innovative process of zeolite synthesis through transforming of natural raw clinker (NRC) via (1) conventional hydrothermal alkaline activation and (2) alkaline fusion prior to hydrothermal reaction. Both methods were evaluated at 100 °C as a function of the alkaline agent, although in the first method other variables such as concentration of the activation solution and reaction time were selected, whereas in the second method similar ratios of alkaline activator/NRC and H2O/alkali fused product during different reaction times were used. Experimental results indicate that the method, alkali activator, concentration and time have a strong effect on the type and degree of crystallinity of the synthesized zeolite. Low-silica sodium or potassium zeolitic materials were synthesized, which include Na-phillipsite, hydroxysodalite and hydroxycancrinite, K-chabazite, zeolite K-F, faujasite and zeolite Linde Type A. The use of a recycling process of NRC in zeolite synthesis could become an area of important interest and research, playing an active role in encouraging and promoting technological advances, research and technology transfer related to the use and disposal of mining wastes, remaining after the natural and spontaneous combustion of coal seams. NRC-based zeolites (NRCZs) synthesized under well-optimized experimental conditions could be used in applications for environmental waste treatment.
    • The influence of water in the synthesis of AlPO4-5 and of zeolite symbol 87 \f "Symbol".

      Cox, Jeffrey J.; Gibbons, M.N.N.; Williams, Craig D. (NISCAIR, 2003)
      The synthesis of the aluminophosphate AlPO4–5 was optimized with regard to water in the formulation and likewise the synthesis of zeolite W. Calculations from published data suggested that optimization occurred when the ions had only their primary hydration sheaths.
    • The synthesis and characterization of Al-Beta and all-silica Beta formed in fluoride and caustic media.

      Brigden, Clive T.; Williams, Craig D. (Amsterdam: Elsevier, 2007)
      The influence of various parameters upon the synthesis of the BEA structure in fluoride and caustic media is investigated and results are compared and related to some previous studies in the literature. High crystalline, low faulted BEA structure has been made in an excess of fluoride (F−/SiO2 ratio of 1.5) across the entire gel Si/Al ratio range of 20 to ∞ using a fumed silica source and in the absence of seed crystals or stirring. Although, for gel Si/Al ratios >20, no aluminium was found in the products. The scope for further investigation of the effects of H2O content and stirring vs. non-stirring upon crystallinity and aluminium uptake, especially in conditions of lower fluoride concentration, is shown. Results from the caustic media syntheses agree with those from previous studies and it is found that the uptake of aluminium into the zeolite during synthesis is required for the formation of the BEA structure. Product characterization of Al-Beta confirms the framework incorporation of aluminium through increased d-spacings, the presence of tetrahedral coordinate aluminium and lowering of the FT-IR external asymmetric stretch and double bend vibration relative to an all-silica sample.
    • Zeolite L Synthesis using Different Molar Gel Compositions for the Purpose of Minimising Reagent Water.

      Wan, Ya; Williams, Craig D.; Duke, Catherine V. A.; Cox, Jeffrey J. (Amsterdam: Elsevier, 2001)
      A new starting molar gel composition 1.3K2O:Al2O3:6.0SiO2:37H2O containing much less silica, potassium and water than a conventional gel composition has been successfully used for the synthesis of zeolite L with minimum chemical waste. Inductively coupled plasma analysis on the mother liquors showed that conversion of 99.7% for Al, 90.9% for Si and 82.2% for K had been achieved when the new gel composition was used for the synthesis. The zeolite L synthesized from the new gel composition showed a well-defined cylindrical morphology. Zeolite L has also been synthesized from two other modified molar gel compositions 1.5K2O:Al2O3:6.0SiO2:37H2O and 1.9K2O:1.0Al2O3:6.0SiO2:67H2O. The chemical waste associated with those two synthesis gel compositions is also greatly reduced.