Electrochemical degradation of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in groundwater

2015 ◽  
Vol 71 (10) ◽  
pp. 1569-1575 ◽  
Author(s):  
A. M. Trautmann ◽  
H. Schell ◽  
K. R. Schmidt ◽  
K.-M. Mangold ◽  
A. Tiehm
Keyword(s):  
Carbon Chain ◽  
Contaminated Groundwater ◽  
Carbon Chain Length ◽  
Order Kinetic ◽  
Electrochemical Degradation ◽  
Boron Doped Diamond ◽  
Polyfluoroalkyl Substances ◽  
Hazardous Pollutants ◽  
Chain Lengths ◽  
Perfluoroalkyl And Polyfluoroalkyl Substances

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) represent hazardous pollutants and are frequently detected in the environment, e.g. in contaminated groundwater. PFASs are persistent to biodegradation and conventional oxidation processes such as ozonation. In this study electrochemical degradation of PFASs on boron-doped diamond (BDD) electrodes is demonstrated. Experiments were performed with model solutions and contaminated groundwater with a dissolved organic carbon (DOC) content of 13 mg/L. The perfluorinated carboxylic acids (PFCAs) perfluorobutanoate, perfluoropentanoate, perfluorohexanoate, perfluoroheptanoate and perfluorooctanoate, and the perfluorinated sulfonic acids (PFSAs) perfluorobutane sulfonate, perfluorohexane sulfonate, perfluorooctane sulfonate and 6:2 fluorotelomer sulfonate were detected in the groundwater samples. At PFAS concentrations ranging from 0.26 to 34 mg/L (0.7 to 79 μM), the degradation of PFASs was achieved despite of the high DOC background. Pseudo first-order kinetic constants of PFSA degradation increased with the increase of carbon chain length. Fluoride formation as well as the generation of PFCAs with shortened chain lengths was observed. Inorganic byproducts such as perchlorate were also formed and have to be considered in further process optimization.

scholarly journals Effect of chemical structure on the sonochemical degradation of perfluoroalkyl and polyfluoroalkyl substances (PFASs)

2016 ◽  
Vol 2 (6) ◽  
pp. 975-983 ◽  
Author(s):  
Nerea Abad Fernandez ◽  
Lucia Rodriguez-Freire ◽  
Manish Keswani ◽  
Reyes Sierra-Alvarez
Keyword(s):  
Chain Length ◽  
Chemical Structure ◽  
Functional Group ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Polyfluoroalkyl Substances ◽  
Perfluoroalkyl And Polyfluoroalkyl Substances

The study provides insights into the effect of carbon chain length, functional group substitutions and chemical structure on sonochemical degradation of perfluoroalkyl and polyfluoroalkyl substances.

The Use of N-alkanes for Estimating Intake and Passage Rate in Horses

1996 ◽  
Vol 1996 ◽  
pp. 98-98
Author(s):  
B M L McLean ◽  
R W Mayes ◽  
F D DeB Hovell
Keyword(s):  
Recent Work ◽  
Chain Length ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Passage Rate ◽  
Forage Crops ◽  
Carbon Chains ◽  
Naturally Occurring ◽  
Chain Lengths ◽  
Long Chain

Alkanes occur naturally in all plants, although forage crops tend to have higher alkane contents than cereals. N-alkanes have odd-numbered carbon chains. They are ideal for use as markers in feed trials, because, they are inert, indigestible and naturally occurring, and can be recovered in animal faeces. Synthetic alkanes (even-numbered carbon chains) are available commercially and can also used as external markers. Dove and Mayes (1991) cite evidence indicating that faecal recovery of alkanes in ruminants increases with increasing carbon-chain length. Thus the alkane “pairs” (e.g. C35 & C36, and C32 & C33) are used in calculating intake and digestibility because they are long chain and adjacent to each other. However, recent work by Cuddeford and Mayes (unpublished) has found that in horses the faecal recovery rates are similar regardless of chain lengths.

scholarly journals Terminal Olefin Profiles and Phylogenetic Analyses of Olefin Synthases of Diverse Cyanobacterial Species

2018 ◽  
Vol 84 (13) ◽  
Author(s):  
Tao Zhu ◽  
Thibault Scalvenzi ◽  
Nathalie Sassoon ◽  
Xuefeng Lu ◽  
Muriel Gugger
Keyword(s):  
Fatty Acid ◽  
Genetic Basis ◽  
Carbon Chain ◽  
Fatty Acyl ◽  
Carbon Chain Length ◽  
Substrate Activation ◽  
Chain Length Specificity ◽  
Modular Architectures ◽  
Terminal Olefins ◽  
Chain Lengths

ABSTRACT Cyanobacteria can synthesize alkanes and alkenes, which are considered to be infrastructure-compatible biofuels. In terms of physiological function, cyanobacterial hydrocarbons are thought to be essential for membrane flexibility for cell division, size, and growth. The genetic basis for the biosynthesis of terminal olefins (1-alkenes) is a modular type I polyketide synthase (PKS) termed olefin synthase (Ols). The modular architectures of Ols and structural characteristics of alkenes have been investigated only in a few species of the small percentage (approximately 10%) of cyanobacteria that harbor putative Ols pathways. In this study, investigations of the domains, modular architectures, and phylogenies of Ols in 28 cyanobacterial strains suggested distinctive pathway evolution. Structural feature analyses revealed 1-alkenes with three carbon chain lengths (C 15 , C 17 , and C 19 ). In addition, the total cellular fatty acid profile revealed the diversity of the carbon chain lengths, while the fatty acid feeding assay indicated substrate carbon chain length specificity of cyanobacterial Ols enzymes. Finally, in silico analyses suggested that the N terminus of the modular Ols enzyme exhibited characteristics typical of a fatty acyl-adenylate ligase (FAAL), suggesting a mechanism of fatty acid activation via the formation of acyl-adenylates. Our results shed new light on the diversity of cyanobacterial terminal olefins and a mechanism for substrate activation in the biosynthesis of these olefins. IMPORTANCE Cyanobacterial terminal olefins are hydrocarbons with promising applications as advanced biofuels. Despite the basic understanding of the genetic basis of olefin biosynthesis, the structural diversity and phylogeny of the key modular olefin synthase (Ols) have been poorly explored. An overview of the chemical structural traits of terminal olefins in cyanobacteria is provided in this study. In addition, we demonstrated by in vivo fatty acid feeding assays that cyanobacterial Ols enzymes might exhibit substrate carbon chain length specificity. Furthermore, by performing bioinformatic analyses, we observed that the substrate activation domain of Ols exhibited features typical of a fatty acyl-adenylate ligase (FAAL), which activates fatty acids by converting them to fatty acyl-adenylates. Our results provide further insight into the chemical structures of terminal olefins and further elucidate the mechanism of substrate activation for terminal olefin biosynthesis in cyanobacteria.

scholarly journals SELECTIVITY OF CANDIDA RUGOSA LIPASE IMMOBILIZED ONTO LAYERED DOUBLE HYDROXIDES AS CATALYST IN SYNTHESIS OF FATTY ACID ESTERS

2016 ◽  
Vol 78 (5-6) ◽  
Author(s):  
Mohd Basyaruddin Abdul Rahman ◽  
Siti Salhah Othman ◽  
Noor Mona Md Yunus
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Chain Length ◽  
Candida Rugosa ◽  
Candida Rugosa Lipase ◽  
Carbon Chain ◽  
Fatty Acid Esters ◽  
Carbon Chain Length ◽  
Chain Lengths ◽  
Acid Esters

The enzymatic selectivity of Lipase from Candida rugosa immobilized onto a calcined layered double hydroxide (CLDHs-CRL) towards the chain-length of fatty acids and alcohols in the synthesis of fatty acid esters was investigated.  The results showed that CMAN-CRL catalyzed the esterification process with fatty acids of medium chain lengths (C10-C14) effectively while, CNAN-CRL and CZAN-CRL exhibited high percentage conversion in fatty acids with carbon chain lengths of C8-C12 and C10-C18, respectively. In the alcohol selectivity study, CMAN-CRL showed high selectivity toward alcohols with carbon chain lengths of C4, C6 and C10.  On the other hand, both CNAN-CRL and CZAN-CRL exhibited rather low selectivity towards longer carbon chain length of alcohols. 

Surface modification model of long afterglow phosphors by saturated fatty acid based Al-Zr coupling agent

2016 ◽  
Vol 45 (5) ◽  
pp. 330-334 ◽  
Author(s):  
Peng Yin ◽  
Can Xue ◽  
Bin Guo
Keyword(s):  
Fatty Acid ◽  
Saturated Fatty Acid ◽  
Coupling Agent ◽  
Water Resistance ◽  
Carbon Chain ◽  
Coupling Agents ◽  
Carbon Chain Length ◽  
Content Type ◽  
Long Afterglow ◽  
Chain Lengths

Purpose The purpose of this paper is to study the influence of different carbon chain lengths in coupling agents on the water resistance and compatibility of modified long afterglow phosphors and attempt to obtain their modification model and mechanism. Design/methodology/approach Three saturated-fatty-acid (caprylic, lauric, stearic acid)-based Al-Zr CAs (coupling agent) was synthesised and applied to modify the long afterglow phosphors SrMgAl4O8:Eu2+,Dy3+. Findings Results show that the coated amount on phosphors decreased from 13.41 to 6.53 per cent with the increased carbon chain length of fatty acid, and the better water resistant and suitability with organic resin can be obtained by lauric-based Al-Zr CA. Originality/value Considering that the decomposition process of modified phosphor was related with the decomposition performance of corresponding coupling agents and original phosphor, a method was first proposed to calculate the coated amount on phosphors by thermogravimetric analyser parameters.

The primary alkylsulfatase of Pseudomonas aeruginosa: inducer specificity and induction kinetics

1982 ◽  
Vol 28 (12) ◽  
pp. 1296-1299 ◽  
Author(s):  
John W. Fitzgerald ◽  
Bobbie L. Franklin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Chain Length ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Induction Kinetics ◽  
Induction Rate ◽  
Inducer Concentration ◽  
Linear Relationships ◽  
Concentration Maximum ◽  
Chain Lengths

The ability of primary alkylsulfate esters and alkanesulfonates to induce alkylsulfatase formation in Pseudomonas aeruginosa was compared on the basis of maximum enzyme levels, induction rate, and levels of induction as a function of inducer concentration. Apparent Kinducer values for these effectors were calculated from linear relationships between reciprocals of induction rate and inducer concentration. Maximum enzyme levels estimated from linear progress relationships for each effector indicated that little major distinction could be made between effectors. Excepting carbon chain lengths of C8 which induced about the same level of enzyme, sulfate esters were generally better inducers than sulfonates with little or no apparent induction occurring with effectors of chain length ≤ C6. These observations also held true when rates were compared, except that the rate for the C8 ester was approximately ninefold greater than that for the analogous sulfonate. Apparent Kinducer constants decreased with increasing alkyl chain length for the esters (C6–C12) and the sulfonates (C8–C14). Values for the esters were approximately sixfold greater than those for sulfonates of equivalent chain length. Plots of log apparent Kinducer values against carbon chain length for each series of esters and sulfonates yielded straight-line relationships characteristic of an homologous series in each instance.

scholarly journals Evaluation of Single and Joint Toxicity of Perfluorinated Carboxylic Acids and Copper to Metal-Resistant Arthrobacter Strains

2019 ◽  
Vol 16 (1) ◽  
pp. 135 ◽  
Author(s):  
Yanping Cai ◽  
Haiyan Chen ◽  
Huilun Chen ◽  
Haiqing Li ◽  
Shuo Yang ◽  
...  
Keyword(s):  
Chain Length ◽  
Carbon Chain ◽  
Growth Rate Constant ◽  
Carbon Chain Length ◽  
Natural Environments ◽  
Joint Toxicity ◽  
Perfluorinated Carboxylic Acids ◽  
Arthrobacter Strain ◽  
Series Of Experiments ◽  
Chain Lengths

Perfluorocarboxylic acid compounds (PFCAs) and copper have been regarded as ubiquitous environmental contaminants in aquatic ecosystems worldwide. However, data on their possible joint toxic effects on microorganisms are still lacking. To study the combined effects of four PFCAs with different carbon chain lengths and copper, a series of experiments were conducted to explore the acute toxicity of these PFCAs in the absence and presence of copper on a metal-resistant Arthrobacter strain GQ-9 by microcalorimetry. The thermokinetic parameters, including growth rate constant (k), inhibitory ratio (I), and half inhibitory concentration (IC50), were calculated and compared using the data obtained from the power-time curves. Our work revealed that GQ-9 is more resistant to perfluorooctanoic acid (PFOA) than Escherichia coli. The single and joint toxicity of PFCAs with copper are dose- and carbon chain length-dependent. The longer the carbon chain length of PFCAs, the higher the toxicity. In addition, PFCAs interacted synergistically with copper. This work could provide useful information for the risk assessment of co-exposure to perfluorinated compounds and heavy metals in natural environments.

Primary Linear Alcohol Ethoxylates as Adjuvants for Primisulfuron

Weed Science ◽  
1994 ◽  
Vol 42 (1) ◽  
pp. 82-85
Author(s):  
Cheryl L. Dunne ◽  
Greg R. Gillespie ◽  
Peter J. Porpiglia
Keyword(s):  
Methyl Ester ◽  
Chain Length ◽  
Carbon Chain ◽  
Alcohol Ethoxylates ◽  
Carbon Chain Length ◽  
Weed Species ◽  
Greenhouse Experiments ◽  
Ethoxylated Alcohols ◽  
Linear Alcohols ◽  
Chain Lengths

Greenhouse experiments were conducted to evaluate the effect of carbon chain length and percent ethoxylation of primary linear ethoxylated alcohols on postemergence control of johnsongrass and quackgrass with primisulfuron. Control of johnsongrass and quackgrass was greatest with primisulfuron plus the experimental ethoxylated alcohols 1412-60 and 1412-70 which had chain lengths of 14 and 12 carbon atoms (60:40 ratio) and 60 or 70% ethoxylation. Control of these two weed species decreased when primisulfuron was applied with ethoxylated linear alcohols of similar chain lengths but decreased percent ethoxylation or with alcohols of similar percent ethoxylation but decreased carbon chain length. Quackgrass and johnsongrass control with primisulfuron plus 1412-60 or 1412-70 was equal to or greater than the control obtained with primisulfuron plus the commercial adjuvants of the nonionic, organosilicone, sunflower methyl ester, or crop oil concentrate types. The experimental adjuvant 1412-70 provided equal or greater uptake and translocation of14C-primisulfuron in johnsongrass and quackgrass compared to four commercial adjuvants.

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