External pressure in the hardening of phosphate in tribofilm on iron surfaces

Purpose: In the present work we consider our (in progress) spectroscopy study of zinc and iron phosphates under the influence external high pressure to determine zinc ion change coordination from tetrahedral to octahedral (or hexahedral) structure.----- Design/methodology/approach: The standard equipment is the optical high pressure cell with diamond (DAC). The DAC is assembled and then vibrational or electronic spectra are collected by mounting the cell in an infrared, Raman, EXAFS or UV-visible spectrometer.----- Findings: Mechanism by which zinc and iron methaphosphate material is transformed to glassy meta-phosphate is enhancing mechanical properties of tribofilm. The two decades of intensive study demonstrates that Zn (II) and Fe (III) ions participate to cross-link network under friction, hardening the phosphate.----- Research limitations/implications: Transition metal atoms with d orbital have flexible coordination numbers, for example zinc acts as a cross-linking agent increasing hardness, by changing coordination from tetrahedral to octahedral. Perhaps the external pressure effect on the [Zn–(O-P-)4 ] complex causes a transformation to an [Zn –(O-P-)6] grouping.----- Originality/value: This paper analyses high-pressure spectroscopy which has been applied for the investigation of 3D transition metal ions in solids. When studying pressure effects on coordination compounds structure, we can expect changes in ground electronic state (spin-crossovers), electronic spectra due to structural distortions (piezochromism), and changes in the ligand field causing shifts in the electronic transitions

Mechanism of hardening for the surface phosphates under external high pressure

Mechanism by which Zn/Fe methaphosphate material is transformed to glassy meta-phosphate is partially understood. The two decades of intensive study demonstrates that Zn and Fe ions participate to cross-link network under friction, hardening the phosphate. In the present work we consider our (in progress) spectroscopy study of zinc and iron phosphates under the influence external high pressure to determine Zn ion change coordination from tetrahedral to octahedral (or hexahedral) structure. The standard equipment is the optical high pressure cell with diamond (DAC). The DAC is assembled and then vibrational or electronic spectra are collected by mounting the cell in an infrared, Raman, EXAFS or UV-visible spectrometer. Transition metal atoms with d orbital have flexible coordination numbers, for example zinc acts as a cross-linking agent increasing hardness, by changing coordination from tetrahedral to octahedral. Perhaps the external pressure effect on the [Zn–(O-P-)4 ] complex causes a transformation to an [Zn –(O-P-)6] grouping High pressure spectroscopy has been extensively applied for the investigation of 3d transition metal ions in solids. When studying pressure effects on coordination compounds structure, we can expect changes in ground electronic state (spin-crossovers), electronic spectra due to structural distortions (piezochromism), and changes in the ligand field causing shifts in the electronic transitions

Determination of oil and grease, total petroleum hydrocarbons and volatile aromatic compounds in soil and sediment samples

This paper describes a case study of petroleum‐contaminated soil/sediment samples which were analyzed using gas chromatography‐flame ionization detector (GC‐FID) for total petroleum hydrocarbons (TPH), volatile aromatic com‐pounds: benzene, toluene, ethylbenzene, and xylenes (BTEX) and naphthalene by GC‐MS, and oil and grease (O/G) con‐tent by sonication in hexane. The ratio of (TPH) / (O/G) shows that the hydrocarbon fraction is between 7% and 87%. The content of volatile organic fraction BTEX accounts for only a small proportion of total TPH, and the ratio of (BTEX) / (TPH) ranges from 0.1% to 0.6%. It should be stressed that the use of TPH methods as against gas chromatography must be done with care because the potential risk posed by BTEX compounds may not be adequately addressed. Santrauka Aprašomi nafta užterštu dirvožemio bei dumblo pavyzdžiai, kuriuose duju chromatografijos būdu GC‐FIDnustatytas bendrasis naftos angliavandeniliu kiekis (TPH), o GC‐MS – lakieji aromatiniai junginiai: benzenas, toluenas, etilbenzenas ir ksilenai (BTEX) bei naftalenas. Sonifikacijos n‐heksane būdu nustatytas alieju ir riebalu (O/G) kiekis. TPH ir O/G santykis rodo, kad angliavandeniliu frakcijos yra nuo 7% iki 87%. Lakioji organine frakcija (BTEX) sudaro palyginti maža bendrojo naftos angliavandeniliu kiekio (TPH) dali, o BTEX ir TPH santykis svyruoja nuo 0,1% iki 0,6%. Ypač vertetu atkreipti demesi i bendrojo naftos angliavandeniliu kiekio (TPH) nustatyma duju chromatografijos būdu, nes galimas lakiosios organines frakcijos (BTEX) pavojingumas gali būti nepakankamai ivertintas. Peзюме Описаны образцы почвы и седимента, в которых способом хроматографии газа GC-FID определено общее количество нефтяных углеводородов (TPH), при помощи GC-MS установлены летучие ароматические соединения: бензол, толуол, этилобензол, ксилолы (BTEX) и нафталин. Способом сонификации в н-гексане определено количество масел и жиров (O/G). Отношение (TPH) / (O/G) свидетельствует о том, что в них содержится от 7% до 87% фракции углеводородов. Летучие ароматические соединения составляют относительно небольшую часть cyммарных нефтяных углеводородов, а отношение (BTEX) / (TPH) колеблется в пределах 0,1–0,6%. Особое внимание следует обратить на определение общего количества нефтяных углеводородов (TPH) способом хроматографии газа в связи с тем, что может быть не полноcтью оценена возможная опасность летучих ароматических соединений (BTEX). First Publish Online: 10 Feb 2011 Reikšminiai žodžiai: dirvožemis ir dumblas, aliejai ir riebalai, bendrasis naftos angliavandenilių kiekis, lakieji aromatiniai junginiai. Ключевые слова: почвa/седимент, маслa и жиры, cyммарные нефтяныe yглеводороды, летучие ароматические соединени

Research on physico-chemical pretreatment of wastewater from the production of wood coating materials

This paper presents the results of the research conducted on the installation designed for physico-chemical pretreatment of technological wastewater in the volume of up to 5.0 m3/day discharged from the production of protective and decorative coating materials used for wooden surfaces. The subject-matter installation constructed on a mobile pallet, consisted of a storage-averaging tank where concentrations were equalised with the use of circulation aeration and mixing. A variant, preliminary pre-oxidation with the use of hydrogen peroxide was conducted in this tank. A substantial installation set for the wastewater treatment plant consisted of two preliminary tube reactors, one cylindrical-conical processing reactor, stations for preparing and dispensing reagents and the sediment dewatering station. Considerable reductions in main chemical indicators of water pollution were obtained in the installation: both total suspended solids (TSS) and ether extract (EE) - more than 98%, chemical oxygen demand (COD) - 46-54%, biochemical oxygen demand (BOD5) - 39-46%, and free formaldehyde (HCHO) - 14-27% due to the use of pre-oxidation and the acid - alkaine double coagulation by applying the ALCAT 105 - SAX 25 system. The use of pre-oxidation with hydrogen peroxide in doses 250.0-450.0 mg/l and then two-stage coagulation resulted in an increase in the reduction of: COD and BOD5 by ca 10-15%, and HCHO by ca 58-66% with reference to the water pretreatment without pre-oxidation. The assessment of sediments formed during the process of pretreatment was made determining the leachable forms of metals (Cu, Ni and Ti) according to methodology of TCLP in compliance with the US EPA Method 1311