The Adsorption of Phosphate on Mica Surfaces

<p>The surface chemistry of the 001 face of cleaved mica sheets was studied with a view to understanding some of the fundamental processes underlying the phenomenon of fixation of phosphate by soils. Radiochemical techniques were developed to make quantitative studies of the adsorption, an important part of these being practical procedures for obtaining sufficient cleanliness and freedeom from airborne contamination. Lack of uniformity of adsorption, as shown by autoradiography, was taken to indicate contamination, and techniques were developed to avid this. Other techniques enabled the continuous monitoring of the sample during adsorption or desorption kinetic experiments. It was shown that adsorption of phosphate on the untreated mica sheets was low, but the adsorption was greatly enhanced if the mica had been treated with aqueous solutions of certain cations such as gallium, aluminium and iron. Form the measurement of the amount of phosphate adsorbed, as a function of the conditions of aluminium treatment, it was concluded that the phosphate could be absorbed by at least three different processes, all of which could be of importance in phosphate fixation by soils. As well as these processes, which occurred on clean, flat, mica surfaces, there were others, involving the edges of mica and sheets, and unknown, but probably organic, films on both mica and air-water surfaces. These could all be of comparable importance in soils. The kinetic measurements of phosphate adsorption and desorption on aluminium-treated mica indicated that many hours were required for attainment of equilibrium, and were quantitatively consistent with the hypothesis that in some cases the adsorption and desorption kinetics were controlled by diffusion of phosphate into particles of some material, possibly a hydrous oxide, adsorbed on the mica. The existence of such particles was supported by the fact that up to one phosphate molecule per two square Angstrom units of mica surface was adsorbed, (and this did not appear to be a value at which the surface was saturated.) Kinetic measurements of 67 Ga sorption processes were consistent with diffusion of gallium through a thin water film, with a diffusion coefficient several orders of magnitude lower than that of single ions in free solution. This may indicate that the gallium was adsorbing as particles, in agreement with the requirements of the phosphate experiments.</p>

The Adsorption of Phosphate on Mica Surfaces

<p>The surface chemistry of the 001 face of cleaved mica sheets was studied with a view to understanding some of the fundamental processes underlying the phenomenon of fixation of phosphate by soils. Radiochemical techniques were developed to make quantitative studies of the adsorption, an important part of these being practical procedures for obtaining sufficient cleanliness and freedeom from airborne contamination. Lack of uniformity of adsorption, as shown by autoradiography, was taken to indicate contamination, and techniques were developed to avid this. Other techniques enabled the continuous monitoring of the sample during adsorption or desorption kinetic experiments. It was shown that adsorption of phosphate on the untreated mica sheets was low, but the adsorption was greatly enhanced if the mica had been treated with aqueous solutions of certain cations such as gallium, aluminium and iron. Form the measurement of the amount of phosphate adsorbed, as a function of the conditions of aluminium treatment, it was concluded that the phosphate could be absorbed by at least three different processes, all of which could be of importance in phosphate fixation by soils. As well as these processes, which occurred on clean, flat, mica surfaces, there were others, involving the edges of mica and sheets, and unknown, but probably organic, films on both mica and air-water surfaces. These could all be of comparable importance in soils. The kinetic measurements of phosphate adsorption and desorption on aluminium-treated mica indicated that many hours were required for attainment of equilibrium, and were quantitatively consistent with the hypothesis that in some cases the adsorption and desorption kinetics were controlled by diffusion of phosphate into particles of some material, possibly a hydrous oxide, adsorbed on the mica. The existence of such particles was supported by the fact that up to one phosphate molecule per two square Angstrom units of mica surface was adsorbed, (and this did not appear to be a value at which the surface was saturated.) Kinetic measurements of 67 Ga sorption processes were consistent with diffusion of gallium through a thin water film, with a diffusion coefficient several orders of magnitude lower than that of single ions in free solution. This may indicate that the gallium was adsorbing as particles, in agreement with the requirements of the phosphate experiments.</p>

An Efficient Simultaneous Degradation of Sulfamethoxazole and Trimethoprim by Photoelectro-Fenton Process Under Non-Modified pH Using a Natural Citric Acid Source: Study of Biodegradability, Ecotoxicity and Antibacterial Activity

In this work, the photoelectro-Fenton system was evaluated as an alternative for the degradation of sulfamethoxazole and trimethoprim at unmodified pH by using citric acid present in extracts from a natural source as organic residues (orange and lemon peels). The addition of natural citric acid showed an efficient degradation of the antibiotics similarly to the efficiency by adding commercial reagent citric acid. The observed high efficiencies and rate constants are attributed to the increment of ferrous ion in the solution due to the fast conversion of iron form its ferric to ferrous state leading to the Fenton reaction and so increasing the hydroxyl radicals production. Although the addition of citric acid present in the extracts slightly increases the organic matter of the solutions, the degradation of the antibiotics was achieved simultaneously and efficiently, converting the photoelectro-Fenton process with the addition of natural citric acid into an alternative ecological system and sustainable for water contaminated with pharmaceutics. Additionally, the high biodegradable character and low ecotoxicity of the treated solutions were determined by a modified Zahn Wellens test and a bioassay with D. magna, respectively. Finally, simultaneous degradation of sulfamethoxazole and trimethoprim was reached after only 45 min of treatment in which the antibacterial activity was completely eliminated, suggesting that degradation products do not represent any environmental risk nor human health.

Cracking of the paraffins on catalysts from natural zeolite of Kazakhstan Shankanay field

Cracking of paraffins was held to obtain long chain α-olefins using the catalysts from natural zeolite of Shankanay field modified with 1N HCl at the temperature range of 500-570°С and atmospheric pressure on a fixed layer. Liquid and gaseous reaction products were analyzed by gas chromatography; regeneration of the catalyst was carried out with a steam-air mixture until total absence of CO2 in the contact gases. To evaluate the structure and texture of the obtained catalysts, the methods of Mössbauer spectroscopy, X-Ray diffractometry analysis, and elemental analysis using scanning electron microscopy were used. As results, zeolite modification allowed doubling the activity of the catalysts and increasing the selectivity by 23.8-44.8%. The group compositions of olefins, alkanes and gaseous products were detected. Iron form under α-Fe2O3, ε-FeOOH and γ-FeOOH was present. The modified and blank form of catalysts under 1N hydrochloric acid solution washing phase content was detected; partial destruction of the crystalline carcass of clinoptilolite was observed.

Fighting Iron-Deficiency Anemia: Innovations in Food Fortificants and Biofortification Strategies

Iron deficiency remains one of the main nutritional disorders worldwide and low iron intake and/or bioavailability are currently the major causes of anemia. To fight this public health problem, the scientific challenge is to find an iron form with sufficient bioavailability to increase its levels in humans through food fortification. In turn, biofortification appears as a comparatively advantageous and bearable strategy for the delivery of vitamins and other micronutrients for people without access to a healthy and diverse diet. This approach relies on plant breeding, transgenic techniques, or agronomic practices to obtain a final food product with a higher iron content. It is also known that certain food constituents are able to favor or inhibit iron absorption. The management of these compounds can thus successfully improve the absorption of dietary iron and, ultimately, contribute to fight this disorder present all over the world. This review describes the main causes/manifestations of iron-deficiency anemia, forms of disease prevention and treatment, and the importance of a balanced and preventive diet. A special focus was given to innovative food fortification and biofortification procedures used to improve the iron content in staple food crops.

Modification of MCM-22 Zeolite and Its Derivatives with Iron for the Application in N2O Decomposition

Layered 2D zeolite MCM-22 and its delaminated derivative, ITQ-2, were modified with iron, by different methods (ion-exchange and direct synthesis), and with the use of different precursors (FeSO4∙7H2O, Fe(NO3)3∙9H2O, and [Fe3(OCOCH3)7∙OH∙2H2O]NO3 oligocations. The applied modifications were aimed at optimization of iron form in the samples (aggregation, amount, location, and reducibility), in order to achieve the highest catalytic activity in the N2O decomposition. The synthesis of the samples was verified with the use of XRD (X-Ray Diffraction), N2-sorption and ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) techniques, while the form of iron in the samples was investigated by UV–vis-DRS (UV–vis diffuse reflectance spectroscopy), H2-TPR (Hydrogen Temperature-Programmed Reduction) and HRTEM (High-Resolution Transmission Electron Microscopy). The highest activity in the N2O decomposition presented the sample Fe(O,IE)MCM-22, prepared by ion-exchange of MCM-22 with Fe3(III) oligocations. This activity was related to the oligomeric FexOy species (the main form of iron in the sample) and the higher loading of active species (in comparison to the modification with FeSO4∙7H2O).

Peningkatan Jumlah Produksi Kerajinan Anyaman Tas Dengan Alat Pemotong Dan Pengukur Tali Pengepak

ABSTRAK Tujuan dari kegiatan ini adalah: 1) Meningkatkan kuantitas dan kualitas produk kerajinan anyaman tas dari limbah tali pengepak di Kabupaten Jember 2) Meningkatkan kemampuan SDM pelaku usaha dan ibu-ibu di lingkungan sekitar usaha. Metode yang digunakan adalah diskusi dan pengumpulan referensi untuk mendesain dan membuat alat pemotong dan pengukur tali plastik, pemberian pelatihan manajemen usaha dan sistem pengelolaan keuangan dan pemberian pelatihan menganyam. Luaran yang dihasilkan adalah alat pemotong dan pengukur tali pengepak. Alat ini terdiri dari 3 komponen, yaitu pisau pemotong, roller dan meja. Pisau pemotong terdiri dari 2 mata pisau yang dihubungkan pada statis geser sehingga dapat digunakan untuk menentukan panjang tali yang diinginkan. Adapun panjang mata pisau adalah 40 cm dengan panjang statis 130 cm. Roller terbuat dari besi silinder dengan ukuran diameter dalam 15 cm dan panjang 26 cm. Meja dengan tinggi 40 cm sebagai alas penyangga alat potong. Hasil potongan tali adalah 10 potongan tali dengan ukuran yang seragam dalam sekali potong. Alat ini telah meningkatkan kuantitas produk yang dihasilkan hingga mencapai 3 kali lipat. Selain itu, juga terjadi peningkatan kualitas dari produk anyaman tas yaitu tas menjadi lebih rapi karena ukuran tali yang seragam. Hasil luaran yang lainnya adalah adanya peningkatan kemampuan SDM pelaku usaha dan ibu-ibu di lingkungan sekitar usaha yang dengan sebelumnya hanya memiliki keterampilan mengayam tali pengepak menjadi mampu menganyam kerajinan anyamanbaru dengan bahan yang lain seperti menganyam tempat buah dari pitrit dan adanya tambahan jenis /model baru dari bentuk tas anyaman yang sudah ada.Kata Kunci: Tali Pengepak, Alat Pemotong dan Pengukur, Tas Anyaman ABSTRACT The direction of this program are: 1) Increasing the quantity and quality of handicraft bag products with matter of waste plastic packing strap in Jember, 2) Improving human resource capacity of agents and mothers in business environment. The method used are discussion and accumulation the reference to design and cause the cutting device and plastic strap gauge, a business management training and financial management system for agents and weave training. The result in this program is cutting device and plastic packing strap gauge. The device are consists of 3 components, are cutter knife, roller, and buffer. The cutting device consists of 2 knifes which are connected to static work so it can be used to determine the desired length of the strap. The length of the knifes is 40 cm with a static length is 130 cm. Roller is made of iron form of cylinder with diameter size of inner is 15 cm and length is 26 cm. Buffer 40 cm of height as a cutting device pedestal. Result of piece a plastic packing strap is can 10 pieces of strings with a uniform size in one to cut. The device has increased the quantity of products produced up to 3 times. In addition, there is also an increase in the quality of woven bag products that becomes more tidy because uniform size of strap.The other outcome is to improvement of human resource capacity the business agents and the mothers in the environment around the business who previously only have the abilityto weave the plastic packing straps to be able to weave new woven crafts with other materials such as weed the fruit of the pitrit and the addition of new types or models of the form of woven bags that have been there before.Keywords: Plastic Packing Strap, Cutting Device And Gauge, Handicraft Bag

Thermogravimetric Analysis of the Zinc Concentrates Oxidation Containing Various Iron Compounds

This paper presents the results of oxidation of zinc concentrates containing various iron compounds. Using the thermogravimetry and thermal analysis methods it was shown that the influence of the iron form affects the thermal oxidation process. They influence the rate of, oxidation of zinc sulphide and consequently the resulting rate of oxidation of the concentrate.

Characterization of CamH from Methanosarcina thermophila, Founding Member of a Subclass of the γ Class of Carbonic Anhydrases

ABSTRACT The homotrimeric enzyme Mt-Cam from Methanosarcina thermophila is the archetype of the γ class of carbonic anhydrases. A search of databases queried with Mt-Cam revealed that a majority of the homologs comprise a putative subclass (CamH) in which there is major conservation of all of the residues essential for the archetype Mt-Cam except Glu62 and an acidic loop containing the essential proton shuttle residue Glu84. The CamH homolog from M. thermophila (Mt-CamH) was overproduced in Escherichia coli and characterized to validate its activity and initiate an investigation of the CamH subclass. The Mt-CamH homotrimer purified from E. coli cultured with supplemental zinc (Zn-Mt-CamH) contained 0.71 zinc and 0.15 iron per monomer and had k cat and kcat /Km values that were substantially lower than those for the zinc form of Mt-Cam (Zn-Mt-Cam). Mt-CamH purified from E. coli cultured with supplemental iron (Fe-Mt-CamH) was also a trimer containing 0.15 iron per monomer and only a trace amount of zinc and had an effective k cat (k cat eff) value normalized for iron that was 6-fold less than that for the iron form of Mt-Cam, whereas the k cat/Km eff was similar to that for Fe-Mt-Cam. Addition of 50 mM imidazole to the assay buffer increased the k cat eff of Fe-Mt-CamH more than 4-fold. Fe-Mt-CamH lost activity when it was exposed to air or 3% H2O2, which supports the hypothesis that Fe2+ has a role in the active site. The k cat for Fe-Mt-CamH was dependent on the concentration of buffer in a way that indicates that it acts as a second substrate in a “ping-pong” mechanism accepting a proton. The k cat/Km was not dependent on the buffer, consistent with the mechanism for all carbonic anhydrases in which the interconversion of CO2 and HCO3 − is separate from intermolecular proton transfer.