A Study of the Mn, Co and Ni Environment in the As-synthesized and Rehydrated-calcined Aluminophosphate with Chabazite-like Topology

Diffuse-reflectance spectroscopy (DRS), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methods are applied to an investigation of Mn, Co and Ni local environments in MnAlPO, CoAlPO, and NiAlPO materials with chabazite-like topology. For all three products, insertion of the transition metals into tetrahedral Al-sites has been found. Calcination and rehydration of the as-synthesised materials cause a change of the oxidation number and co-ordination geometry of Mn and Co, while the oxidation and co-ordination number of Ni remain unaffected

Microwave-Assisted Depolymerisation of Biolignintm in the Presence of Zeolite-Based Catalysts

In this work a microwave-assisted depolymerisation of lignin in the presence of zeolite-based catalysts was studied in order to obtain a valuable bio-oil. Catalytic activity of H-ZSM-5, H-Y, H-BETA and H-Mordenite containing nano-NiO particles was investigated in the depolymerisation of BioligninTM. The catalysts were prepared by mechanochemical dry milling (MCDM) method following by calcination under air at 400 °C. The highest bio-oil yield of 8.78 wt. %, was obtained in the presence of NiO-containing H-ZSM-5

Synthesis and Characterization of Amorphous Nickel(II) Aluminosilicate

Amorphous aluminosilicates containing about 12 wto °/0 nickel have been synthesized bycation exchange. Approximately 40°/0 of the nickel content is present in the form of octahedral [NiH20)6]2+ ions while the bulk of NF+ is coordinated both by I-hO molecules and by oxygen atoms of the aluminosilicate framework. When the materials are heated in air at 350 -c, a change in the nickel coordination environment/geornetry and possibly also a partial oxidation take place

On a Possible Role of Dicarboxylate Ions in the Formation of Open-framework Metallophosphates

Three dicarboxylic acids (oxalic, malonic and terephthalic) were investigated as possible pillars in the formation of metallophosphates with extended structures in the presence of 1,2-diaminopropane (DAP) as a structure-directing agent. Only the oxalate ion was proven to be a suitable building block in the formation of hybrid networks. The terephthalate ion seems to possess the ability to be structurally involved in lattice formation, although not in networks of the hybrid type. The malonate ion in this system showed no propensity towards lattice formation, i.e., malonic acid merely exits as an intercalated species inside the 2–D zincophosphate structure. Different pillar-functioning ability has been attributed to structural differences of the three dicarboxylate ions

The use in grass production of clinoptilolite as an ammonia adsorbent and a nitrogen carrier

Clinoptilolite-rich tuff (NZ) from the Zlatokop deposit (Vranjska Banja, Serbia) was studied as a nitrogen carrier for grass production. The mechanism of binding ammonium cations present in aqueous solutions by NZ was examined, as well as the possibility of adsorption of ammonia released in fresh cattle manure during its fermentation. The NH4+ binding from solutions proceeded via an ion-exchange process that followed pseudo-second-order kinetics. Adsorption isotherms studied at 298-318 K followed the Freundlich isotherm equation. The NZ readily adsorbs ammonia liberated from manure and the addition of 10 wt. % of NZ to manure can preserve up to 90 % of ammonia. The potential benefit of this effect was examined in greenhouse pot experiments with Italian ryegrass (Lolium multiflorum, var. Macho) using three different types of soil (silty, clayey and sandy). The zeta potential measurements showed that the stability of their colloidal dispersions differed mutually and that the addition of NZ affected the stability and nitrogen cycling differently. All results indicated that NZ could be applied in grass production

On a Possible Role of Dicarboxylate Ions in the Formation of Open-framework Metallophosphates

Three dicarboxylic acids (oxalic, malonic and terephthalic) were investigated as possible pillars in the formation of metallophosphates with extended structures in the presence of 1,2-diaminopropane (DAP) as a structure-directing agent. Only the oxalate ion was proven to be a suitable building block in the formation of hybrid networks. The terephthalate ion seems to possess the ability to be structurally involved in lattice formation, although not in networks of the hybrid type. The malonate ion in this system showed no propensity towards lattice formation, i.e., malonic acid merely exits as an intercalated species inside the 2–D zincophosphate structure. Different pillar-functioning ability has been attributed to structural differences of the three dicarboxylate ions

A Study of the Mn, Co and Ni Environment in the As-synthesized and Rehydrated-calcined Aluminophosphate with Chabazite-like Topology

Diffuse-reflectance spectroscopy (DRS), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methods are applied to an investigation of Mn, Co and Ni local environments in MnAlPO, CoAlPO, and NiAlPO materials with chabazite-like topology. For all three products, insertion of the transition metals into tetrahedral Al-sites has been found. Calcination and rehydration of the as-synthesised materials cause a change of the oxidation number and co-ordination geometry of Mn and Co, while the oxidation and co-ordination number of Ni remain unaffected

Novel material for medical use based on Ag-zeolite/polyvinyl chloride composite

The aim of this work was to study antibacterial activity of silver-exchanged natural clinoptilolite/polyvinil chloride composites (AgZ/PVC) toward clinical isolates of Acinetobacter baumannii, which causes various nosocomial infection. Polyvinil chloride (PVC) mostly used for endotracheal tubes usually acts as a reservoir for bacteria causing infections with a high level of mortality

PREPARATION, CHARACTERIZATION AND ANTIBACTERIAL ACTIVITY OF CLINOPTILOLITE/THYMOL COMPOSITES

Composites based on natural zeolite – clinoptilolite and thymol were prepared using two different approaches: 1) wet impregnation (WI) and supercritical solvent impregnation (SSI). The SSI was more superior since it yielded the composite with higher amount of thymol and with stronger thymol-clinoptilolite interactions than WI. The composites exhibited antibacterial activity towards Gram-negative bacteria Escherichia coli and Grampositive bacteria Staphylococcus aureus suggesting its applicability for disinfectant purposes

Lignin pyrolysis in the presence of oxide particles embedded onto natural clinoptilolite and ZSM-5

A main objective of this work was to investigate and compare catalytic activity of the natural clinoptilolite (NZ) and ZSM-5 which are modified with several oxide species: NiO, Cu2O, MgO and CaO in the pyrolysis of softwood and hardwood lignin. The lignocellulose as cheapest and most abundant source of biomass has attracted considerable attention as very promising substitute for fossil fuels