Determination of Manganese in Tri Calcium Phosphate (TCP) by Atomic Absorption Spectrometry

Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standards. A number of analytical methods are presently used for the analysis of metals in the biochemical. The instrumental techniques available are Inductively Coupled Plasma (ICP/MS), X-Ray Fluorescence, UV-VIS Spectrophotometry, and Atomic Absorption Spectrometry. Flame AA has gained widespread acceptance as an analytical technique and is used for many applications. In this study, we have determined the amount of manganese metal present in Tricalcium Phosphate (TCP) using Flame Atomic Absorption Spectrophotometer. The method has high precision and accuracy. The percent recovery was found to be 99.8% for spiked sample. The results meet the requirement.

Biodegradation pathway and mechanism of tri (2-chloropropyl) phosphate by Providencia rettgeri

Tri(2-chloropropyl)phosphate(TCPP)was an emerging contaminant of global concern because of its frequent occurrence,potential toxic effects,and persistence in the environment.Microbial degradation might be an efficient and safe removal method,but limited information was available.In this study,Providencia rettgeri was isolated from contaminated sediment and showed it could use TCPP as unique phosphorus source to promote growth,and decompose 34.7%of TCPP(1 mg/L)within 5 days.The microbial inoculation and the initial concentration of TCPP could affect the biodegradation efficient.Further study results indicated that TCPP decomposition by Providencia rettgeri was mainly via phosphoester bond hydrolysis,evidenced by the production of bis(2-chloropropyl)phosphate(C_(6)H_(13)Cl_(2)PO_(4))and mono-chloropropyl phosphate(C_(3)H_(8)ClPO_(4)).Both intracellular and extracellular enzymes could degrade TCPP,but intracellular degradation was dominant in the later reaction stage,and the presence of Cu^(2+) ions had a promoting effect.These findings developed novel insights into the potential mechanism of TCPP microbial degradation.

UV/H2O2 oxidation of tri(2-chloroethyl) phosphate: Intermediate products, degradation pathway and toxicity evaluation

Tri(2-chloroethyl) phosphate(TCEP) with the initial concentration of 5 mg/L was degraded by UV/H2O2 oxidation process. The removal rate of TCEP in the UV/H2O2 system was 89.1% with the production of Cl-and PO4^3- of 0.23 and 0.64 mg/L. The removal rate of total organic carbon of the reaction was 48.8% and the pH reached 3.3 after the reaction. The oxidative degradation process of TCEP in the UV/H2O2 system obeyed the first order kinetic reaction with the apparent rate constant of 0.0025 min^-1( R^2 = 0.9788). The intermediate products were isolated and identified by gas chromatography-mass spectrometer. The addition reaction of HO · and H2O and the oxidation reaction with H2O2 were found during the degradation pathway of 5 mg/L TCEP in the UV/H2O2 system. For the first time, environment risk was estimated via the "ecological structure activity relationships" program and acute and chronic toxicity changes of intermediate products were pointed out. The luminescence inhibition rate of photobacterium was used to evaluate the acute toxicity of intermediate products. The results showed that the toxicity of the intermediate products increased with the increase of reaction time, which may be due to the production of chlorine compounds. Some measures should be introduced to the UV/H2O2 system to remove the highly toxic Cl-containing compounds, such as a nanofiltration or reverse osmosis unit.

Enhanced CO_2 adsorptive performance of PEI/SBA-15 adsorbent using phosphate ester based surfactants as additives

In this study,a series of polyetherimide/SBA-15： 2-D hexagonal P6 mm,Santa Barbara USA（PEI/SBA-15） adsorbents modified by phosphoric ester based surfactants（including tri（2-ethylhexyl）phosphate（TEP）,bis（2-ethylhexyl） phosphate（BEP） and trimethyl phosphonoacetate（TMPA））were prepared for CO2 adsorption.Experimental results indicated that the addition of TEP and BEP had positive effects on CO2 adsorption capacity over PEI/SBA-15.In particular,the CO2 adsorption amount could be improved by around 20% for 45PEI-5TEP/SBA-15 compared to the additive-free adsorbent.This could be attributed to the decrease of CO2 diffusion resistance in the PEI bulk network due to the interactions between TEP and loaded PEI molecules,which was further confirmed by adsorption kinetics results.In addition,it was also found that the cyclic performance of the TEP-modified adsorbent was better than the surfactant-free one.This could be due to two main reasons,based on the results of in situ DRIFT and TG-DSC tests.First and more importantly,adsorbed CO2 species could be desorbed more rapidly over TEP-modified adsorbent during the thermal desorption process.Furthermore,the enhanced thermal stability after TEP addition ensured lower degradation of amine groups during adsorption/desorption cycles.

Chlorinated organophosphate and“legacy”brominated flame retardants in UK waste soft furnishings:A preliminary study

The Furniture and Furnishings(Fire Safety)Regulations 1988 is the major driver for the use of chemical flame retardants(FRs)in soft furnishings marketed in the UK.While these regulations specify the level of flame retardancy required,they do not specify how such levels should be achieved.Consequently,it remains unclear which FRs are present in UK soft furnishings.This is important not only to help assess what FRs we may be exposed to currently,but which FRs are currently entering the waste stream with concomitant potential for release into the environment.To address this data gap,concentrations of polybrominated diphenyl ethers(PBDEs),hexabromocyclododecane(HBCDD)and a range of chlorinated organophosphate flame retardants(OPFRs)were measured in samples of domestic and office waste soft furnishings products entering the UK waste stream in 2011 and 2012.This preliminary study measured the FR content of:carpets(n?4),curtains(n?7),mattress fabrics(n?2),furniture foam(n?9),and furniture upholstery textiles(n?10).Polybrominated diphenyl ethers(PBDEs)and hexabromocyclododecane(HBCDD)were not found at significant concentrations(below detection limits in most samples)in any of the twenty two analysed products.In contrast,7 of the 9 furniture foam samples were treated with tris(2-chloroisopropyl)phosphate(TCIPP)at a mean concentration of 1.9%w/w,with another single foam sample containing tris(1,3-dichloroisopropyl)phosphate(TDCIPP)and tris(2-chloroethyl)phosphate(TCEP)at 1.1 and 0.5%respectively.By comparison,PBDE concentrations are within the range reported previously for UK indoor dust[18],rather than the percent by weight levels required to impart flame retardancy.