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Quantum yields pollutants

Jinxia Xu, Zhangjun Bai, Fanlin Zu, Fanyong Yan, Junfu Wei, Saihui Zhang, Yunmei Luo
A convenient, highly sensitive and reliable assay for 2,4,6‑trinitrophenol (TNP) and Fe (III) ion (Fe3+ ) in the dual spectroscopic manner is developed based on novel carbon dots (CDs). The CDs with highly blue emitting fluorescent were easily prepared via the one-step potassium hydroxide-assisted reflux method from dextrin. The as-synthesized CDs exhibited the high crystalline quality, the excellent fluorescence characteristics with a high quantum yield of ~13.1%, and the narrow size distribution with an average diameter of 6...
April 10, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Lu Zhang, Yasutomo Hoshika, Elisa Carrari, Kent O Burkey, Elena Paoletti
Tropospheric ozone (O3 ) is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O3 damage, several agrochemicals have been assessed, including cytokinin (e.g., kinetin, KIN) and ethylenediurea (EDU) with cytokinin-like activity. In higher plant, leaves are primarily injured by O3 and protective agrochemicals are often applied by leaf spraying. To our knowledge, the mitigating abilities of EDU and KIN have not been compared directly in a realistic setup. In the present research, impacts of elevated O3 (2× ambient O3 , 24hr per day, for 8days) on an O3 sensitive line (S156) of snap bean (Phaseolus vulgaris), which is often used for biomonitoring O3 pollution, were studied in a free air controlled exposure system...
April 2018: Journal of Environmental Sciences (China)
Paula S M Celis-Plá, Murray T Brown, Alex Santillán-Sarmiento, Nathalie Korbee, Claudio A Sáez, Félix L Figueroa
Global scenarios evidence that contamination due to anthropogenic activities occur at different spatial-temporal scales, being important stressors: eutrophication, due to increased nutrient inputs; and metal pollution, mostly derived from industrial activities. In this study, we investigated ecophysiological and metabolic responses to copper and nutrient excess in the brown macroalga Cystoseira tamariscifolia. Whole plants were incubated in an indoor system under control conditions, two levels of nominal copper (0...
March 2018: Marine Pollution Bulletin
Chao Tai, Shaodong Zhang, Yongguang Yin, Zhifeng Dai, Yanbin Li, Guibin Jiang, Yong Cai, Chunhua Huang, Jianbo Shi
A simple, clean, and efficient method has been developed for generating hydroxyl radicals on a nitrocellulose membrane (NCM) under light of wavelengths greater than 280 nm. Hydroxyl radicals formed on the NCM surface, diffusing into the bulk solution under irradiation. Radical generation was shown to be dependent on the nature of the NCM and light, and independent of the properties of the bulk solution. The quantum yield for hydroxyl radicals from the NCM was 1.72×10-4 , which is approximately 2.46 times that from TiO2 ...
March 9, 2018: ChemSusChem
Poushali Das, Sayan Ganguly, Priti Prasanna Maity, Madhuparna Bose, Subhadip Mondal, Santanu Dhara, Amit Kumar Das, Susanta Banerjee, Narayan Ch Das
Proper waste disposal from household and restaurants is becoming an important and recurring waste-management concern. Herein, a method of upcycling of waste kitchen chimney oil has been adopted to prepare fluorescent multifunctional carbon quantum dots. These nanodots showed superior biocompatibility, excellent optical properties, water solubility and high yield. Preparation of C-dots from highly abundant carbon source of waste refusals is highly effective in commercial aspect as well as in reducing the immense environmental pollution...
March 2018: Journal of Photochemistry and Photobiology. B, Biology
M S Swapna, S Sankararaman
The present work describes a solution for the effective use of the hazardous particulate matter (diesel soot) from the internal combustion engines (ICEs) as a potential material emitting white light for white light emitting diodes (WLEDs). The washed soot samples are subjected to Field Emission Scanning Electron Microscopy (FESEM), High- Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive Spectroscopy (EDS), UV-Visible, Photoluminescent (PL) Spectroscopy and quantum yield measurements. The CIE plot and Correlated Color Temperature (CCT) reveals the white fluorescence on photoexcitation...
February 5, 2018: Journal of Fluorescence
Jingjing Chu, Fan Zhu, Xiaoyong Chen, Huizi Liang, Renjie Wang, Xuxu Wang, Xinhao Huang
Contamination by heavy metals has become a serious environmental pollution issue today due to its potential threat to plant, wildlife, and human health. Photosynthesis, a process in which light energy is used to produce sugar and other organic compounds, is sensitive to heavy metals. In the present study, the response of photosynthetic process and carbon assimilation of Schima superba was investigated under cadmium (Cd) stress. Three Cd concentrations (0, 300, and 600 mg kg-1 ) were used designated as control (CK), low Cd (L1 ), and high Cd treatment (L2 ) of plants...
April 2018: Environmental Science and Pollution Research International
Manuvesh Sangwan, Lei Zhu
Methyl-substituted 2-nitrophenols are important components of "brown carbon" from biomass burning. Photolysis is their major gas-phase degradation pathway. To determine the extent of light absorptions by 4-methyl-2-nitrophenol and 5-methyl-2-nitrophenol, we obtained their absorption cross sections in the 295-400 nm region by using cavity ring-down spectroscopy. Cross-section values for 4-methyl-2-nitrophenol were (1.01 ± 0.07) × 10-18 , (5.72 ± 0.39) × 10-18 , and (1.80 ± 0.17) × 10-20 cm2 /molecule at 295, 345, and 400 nm, where errors quoted represent 1σ measurement uncertainty...
February 22, 2018: Journal of Physical Chemistry. A
Pengchao Xie, Siyang Yue, Jiaqi Ding, Ying Wan, Xuchun Li, Jun Ma, Zongping Wang
Vacuum-Ultraviolet (VUV), an efficient and green method to produce hydroxyl radical (•OH), is effective in degrading numerous organic contaminants in aqueous solution. Here, we proposed an effective and simple kinetic model to describe the degradation of organic pollutants in VUV system, by taking the •OH scavenging effects of formed organic intermediates as co-existing organic matter in whole. Using benzoic acid (BA) as a •OH probe, •OH was regarded vital for pollutant degradation in VUV system, and the thus developed model successfully predicted its degradation kinetics under different conditions...
April 15, 2018: Water Research
Holger V Lutze, Julia Brekenfeld, Sergej Naumov, Clemens von Sonntag, Torsten C Schmidt
Perfluorinated organic compounds (PFC) are an important group of pollutants, which are difficult to be degraded in conventional water treatment. Even hydroxyl radical based processes are not capable to degrade these compounds. Sulfate radicals can oxidize a group of PFC, i.e., perfluorinated carboxylic (PFCAs) acids. However, information in literature on kinetics and reaction mechanism is largely based on model simulations which are prone to errors. The present study provides mechanistic insights based on product formation, material balances, competition kinetics experiments and quantum chemical calculations...
February 1, 2018: Water Research
Dinesh Kumar, Sang Bong Lee, Chan Hee Park, Cheol Sang Kim
Here, we report the preparation of various morphologies of core-satellite hybrid plasmonic nanomaterials of gold and platinum, viz., the coating of platinum nanoparticles on gold nanostars (Pt@AuNSs), nanospheres (Pt@AuNPs), and nanorods (Pt@AuNRs) for visible-NIR-sunlight illuminated highly efficient photoconversion of CO2 to HCOOH and visible light mediated degradation of various organic dyes (methylene blue, methyl orange, and methyl red) in a single step at room temperature. In comparison, Pt@AuNSs shows higher conversion efficiency for CO2 photoconversion to HCOOH with 1...
January 10, 2018: ACS Applied Materials & Interfaces
Thanh Hoai Tran, Einav Mayzlish Gati, Amram Eshel, Gidon Winters
Along the arid Arava, southern Israel, acacia trees (Acacia raddiana and Acacia tortilis) are considered keystone species. Yet they are threatened by the ongoing aquifer depletion for agriculture, the conversion of natural land to agricultural land, seed infestation by bruchid beetles, and the reduction in precipitation level in the region. In the acacia dominated Evrona reserve (southern Arava), adding to these threats are recurrent oil spills from an underground pipeline. We report here a study of the effects of contaminated soils, from a recent (December 2014) and a much older (1975) oil spills...
March 2018: Environmental Pollution
Yang-Er Chen, Hao-Tian Mao, Jie Ma, Nan Wu, Chao-Ming Zhang, Yan-Qiu Su, Zhong-Wei Zhang, Ming Yuan, Huai-Yu Zhang, Xian-Yin Zeng, Shu Yuan
We systematically compared the impacts of four Cr salts (chromic chloride, chromic nitrate, potassium chromate and potassium bichromate) on physiological parameters and chlorophyll fluorescence in indigenous moss Taxiphyllum taxirameum. Among the four Cr salts, K2 Cr2 O7 treatment resulted in the most significant decrease in photosynthetic efficiency and antioxidant enzymes, increase in reactive oxygen species (ROS), and obvious cell death. Different form the higher plants, although hexavalent Cr(VI) salt treatments resulted in higher accumulation levels of Cr and were more toxic than Cr(III) salts, Cr(III) also induced significant changes in moss physiological parameters and chlorophyll fluorescence...
March 2018: Chemosphere
Heming Zhang, Xiaoxuan Wei, Xuedan Song, Shaheen Shah, Jingwen Chen, Jianhui Liu, Ce Hao, Zhongfang Chen
For organic pollutants, photodegradation, as a major abiotic elimination process and of great importance to the environmental fate and risk, involves rather complicated physical and chemical processes of excited molecules. Herein, we systematically studied the photophysical and photochemical processes of a widely used antibiotic, namely sulfapyridine. By means of density functional theory (DFT) computations, we examined the rate constants and the competition of both photophysical and photochemical processes, elucidated the photochemical reaction mechanism, calculated reaction quantum yield (Φ) based on both photophysical and photochemical processes, and subsequently estimated the photodegradation rate constant...
January 2018: Chemosphere
Vanessa Hörmann, Klaus-Reinhard Brenske, Christian Ulrichs
Three common plant species (Dieffenbachia maculata, Spathiphyllum wallisii, and Asparagus densiflorus) were tested against their capacity to remove the air pollutants toluene (20.0 mg m-3 ) and 2-ethylhexanol (14.6 mg m-3 ) under light or under dark in chamber experiments of 48-h duration. Results revealed only limited pollutant filtration capabilities and indicate that aerial plant parts of the tested species are only of limited value for indoor air quality improvement. The removal rate constant ranged for toluene from 3...
January 2018: Environmental Science and Pollution Research International
Li Ling, Heather Tugaoen, Jonathon Brame, Shahnawaz Sinha, Chuanhao Li, Jared Schoepf, Kiril Hristovski, Jae-Hong Kim, Chii Shang, Paul Westerhoff
A photocatalyst-coated optical fiber was coupled with a 318 nm ultraviolet-A light emitting diode, which activated the photocatalysts by interfacial photon-electron excitation while minimizing photonic energy losses due to conventional photocatalytic barriers. The light delivery mechanism was explored via modeling of evanescent wave energy produced upon total internal reflection and photon refraction into the TiO2 surface coating. This work explores aqueous phase LED-irradiated optical fibers for treating organic pollutants and for the first time proposes a dual-mechanistic approach to light delivery and photocatalytic performance...
November 2, 2017: Environmental Science & Technology
Jiliang Ci, Ye Tian, Shigenori Kuga, Zhongwei Niu, Min Wu, Yong Huang
The doping of nitrogen into carbon quantum dots is vitally important for improved fluorescence performance. However, the synthesis of nitrogen-doped carbon quantum dots (N-CQDs) is usually conducted under strong acid and high temperature, which results in environmental pollution and energy consumption. Herein, the N-CQDs were prepared by a mild one-pot hydrothermal process. The hydrothermal reaction temperature was adjusted to control the particle size, nitrogen/carbon atomic ratio, and quantum yield. The products were water soluble with a narrow particle size distribution and good dispersion stability over a wide pH range...
November 16, 2017: Chemistry, An Asian Journal
Tsung-Rong Kuo, Shih-Ting Hung, Yen-Ting Lin, Tzu-Lin Chou, Ming-Cheng Kuo, Ya-Pei Kuo, Chia-Chun Chen
Quantum dot light-emitting diodes (QD-LEDs) have been considered as potential display technologies with the characterizations of high color purity, flexibility, transparency, and cost efficiency. For the practical applications, the development of heavy-metal-free QD-LEDs from environment-friendly materials is the most important issue to reduce the impacts on human health and environmental pollution. In this work, heavy-metal-free InP/ZnS core/shell QDs with different fluorescence were prepared by green synthesis method with low cost, safe, and environment-friendly precursors...
September 19, 2017: Nanoscale Research Letters
Bijoli Mondal, Asok Adak, Pallab Datta
This work investigates the degradation kinetics of a recalcitrant organic pollutant, cetyltrimethylammonium bromide (CTAB), using direct UV and UV-H2O2 advanced oxidation processes. Direct photolysis at 253.7 nm showed only 55% degradation upto fluence dose of 40.65 J/cm(2) for initial CTAB concentration of 100 mg/L. The apparent fluence-based pseudo-first order rate constant and quantum yield were 2.29(±0.325)×10(-5) cm(2)/mJ and 0.305(±0.043) mol/Einstein respectively. In case of UV-H2O2, > 99% degradation was observed upto fluence dose of 0...
August 9, 2017: Environmental Technology
Andrew J McCabe, William A Arnold
Dissolved organic matter (DOM) quantity and composition control the rate of formation (Rf,T) of triplet excited states of dissolved natural organic matter ((3)DOM*) and the efficiency of (3)DOM* formation (the apparent quantum yield, AQYT). Here, the reactivity of (3)DOM* in stormflow samples collected from watersheds with variable land covers is examined. Stormflow DOM reflects variability in DOM quantity and composition as a function of land cover and may be important in controlling the fate of cotransported pollutants...
August 16, 2017: Environmental Science & Technology
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