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A nitrite sensor based on immobilized Dawson-type tungstophosphate α-K7[H4PW18O62]·18H2O (PW18) in multilayers of charged polyelectrolyte poly(allylamine hydrochloride) (PAH) on a glassy carbon electrode is described. A nitrite sensor manufactured with 10 layers has a sensitivity of ∼4 nA/μM nitrite, fast response time (<6 s), low detection limit (∼0.1 μM), high selectivity towards endogenous interferences such as nitrate and molecular oxygen, a linear range from 0.1 μM to at least 20 mM nitrite and was stable for at least 2 months. In addition, such nitrite sensors can operate in a pH range from 1 to 9, and the sensitivity can be increased by increasing the number of layers at the expense of increasing the response time. 相似文献
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Hassen Khazri Ibtissem Ghorbel‐Abid Sihem Ben Hassine Sylvie Chevolleau Laurent Debrauwer Rafik Kalfat Malika Trabelsi‐Ayadi 《Journal of separation science》2019,42(9):1710-1716
In this work, clay‐Na particles are used as the adsorbent for the solid‐phase extraction of acidic compounds. The novel sorbent under study is based on high‐specific surface area, cation‐exchange capacity designed specifically to offer ion‐exchange properties with the goal being to selectively extract a group of acidic compounds. The effects of the extraction parameters including extraction elution solvent, sample volume and pH. In optimum conditions, the repeatability for one fiber (n = 3), expressed as % relative standard deviation, was between 0.3 and 4.3% for the acid compounds. The detection limits for the studied acidic compounds were between 0.1–0.6 μg/L. The developed method offers the advantages of being simple to use and having a low cost of equipment. 相似文献
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Evan W. Muller Alfred A. Burney-Allen Jessica Shaw David L. Wheeler Volodimyr Duzhko Malika Jeffries-EL 《Journal of polymer science. Part A, Polymer chemistry》2020,58(9):1299-1310
The use of direct C H arylation cross-coupling polymerization was evaluated for the synthesis of donor–acceptor conjugated co-polymers using the novel donor 1,6-didecylnaphtho[1,2-b:5,6-b']difuran and either thieno[3,4-c]pyrrole-4,6-dione (TPD) or 1,4-diketopyrrolo[3,4-c]pyrrole (DPP) as the acceptor. Thiophene and furan moieties were used to flank the DPP group and the impact of these heterocycles on the polymers' properties was evaluated. The alkyl chains on the diketopyrrolopyrrole monomers were varied to engineer the solubility and morphology of the materials. All of the polymers have similar optoelectronic properties with narrow optical band gaps around 1.3 eV, which is ideal for solar energy harvesting. Unfortunately, these polymers also had high-lying highest occupied molecular orbital levels of −4.8 to −5.1, and as a result bulk-heterojunction photovoltaic cells fabricated using the soluble fullerene derivative PC71BM as the electron-acceptor and these polymers as donor materials exhibited poor performance due to limited Voc values. An examination of the films from these blends indicates that film-thickness and morphology were also a major hindrance to performance and a potential point of improvement for future materials. 相似文献
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Photocatalytic Degradation of Oxytetracycline in Aqueous Solutions with TiO2 in Suspension and Prediction by Artificial Neural Networks
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In this study, the photocatalytic degradation of oxytetracycline (OTC) in aqueous solutions has been studied under different conditions such as initial pollutant concentrations, amount of catalyst, and pH of the solution. Experimental results showed that photocatalysis was clearly the predominant process in the pollutant degradation, since OTC adsorption on the catalyst and photolysis are negligible. The optimal TiO2 concentration for OTC degradation was found to be 1.0 g/L. The apparent rate constant decreased, and the initial degradation rate increased with increasing initial OTC concentration with the other parameters kept unchanged. Subsequently, data obtained from photocatalytic degradation were used for training the artificial neural networks (ANN). The Levenberg–Marquardt algorithm, log sigmoid function in the hidden layer, and the linear activation function in the output layer were used. The optimized ANN structure was four neurons at the input layer, eighteen neurons at the hidden layer, and one neuron at the output layer. The application of 18 hidden neurons allowed to obtain the best values for R2 and the mean squared error, 0.99751 and 7.504e–04, respectively, showing the relevance of the training, and hence the network can be used for final prediction of photocatalytic degradation of OTC with suspended TiO2. 相似文献
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Samia Bouzroura Lamouri Hammal Fadila Balegroune Malika Hamadène Sophie Poulain 《合成通讯》2013,43(3):448-455
High‐yielding syntheses of an unpublished series of 2‐thioxo‐imidazolidin‐4‐ones 6 bearing an N‐ethoxycarbonyl and amidyl moieties an N1 and C5, respectively, are reported. These derivatives were obtained by intramolecular cyclization of 3‐ethylhydrazinoacetate 3,4‐dihydro maleimides 4 in the presence of ethyl or phenylisothiocyanate 2 under neutral conditions. 相似文献
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Malika Ibrahim-Ouali Marie-Eve Sinibaldi Yves Troin Daniel Gardette Jean-Claude Gramain 《合成通讯》2013,43(11):1827-1848
The synthesis of original allenic lactams 2 and allenic esters 5 is presented and their Michael condensation with N-benzylaniline described. 相似文献