Trace Organic Substances Research Articles

Fe3+-modified polyamide membrane with a porous network structure: Rapid permeation and efficient interception of trace organic compounds

Forward osmosis (FO) is a promising technology in the treatment of trace organic substances. However, the development of this technology is limited by membrane material selection and the long-term chemical stability and durability of the membrane. Whereas ibuprofen, a representative trace organic substances that is hydrophobic and negatively charged, poses potential environmental hazards due to its bioactivity. In this work, polyethersulfone (PES) membranes were modified with iron metal complexes via chelation reactions to achieve high rejection rates for ibuprofen. The Fe3+-modified composite FO membrane increased the ibuprofen rejection rate to 98.3 % compared to less than 80.0 % for the original PES membrane. Additionally, the modified membrane enhanced water flux by at least 25.0 % and reduced reverse solute flux to a maximum of 73.0 % of that of the polyamide composite membrane, while significantly improving anti-fouling capabilities. Membrane characterization results revealed that the significant enhancement in the ibuprofen retention rate was due to the addition of a negative charge by forming complexes with Fe3+, which increased intermolecular interactions. Additionally, the dense network structure developed by the Fe3+-EDTA-2Na modification also contributed to the enhanced membrane performance.

Ionic solvent-mediated electrolytic decontamination of pesticide-containing wastewater

Abstract This study investigated the performance of different ionic solvents (NaCl, KNO3, and Na2SO4) in mediating electrolytic decontamination of pesticide-containing wastewaters and established the most suitable ionic solvent that can satisfactorily achieve decontamination of such wastewaters. These were done to find a water-purification technique suitable for the removal of recalcitrant and hazardous trace organic substances from wastewater. Organochlorine pesticide (OCP)-containing wastewaters were constituted according to prescribed modalities. It was observed that complete decontamination of the wastewater was achieved within 2 h of using Na2SO4. The study concluded that the 1.0 M of Na2SO4 solution-mediated electrolytic process was most efficient in decontaminating OCP-containing wastewater.

An eco-friendly method using deep eutectic solvents immobilized in a microcrystal cellulose-polyvinyl alcohol sponge for parabens analysis in food samples

An eco-friendly, simple, and reusable deep eutectic solvents (DESs)–microcrystal cellulose (MCC)–polyvinyl alcohol (PVA) sponge was synthesized using DESs adsorbed on MCC (DESs–MCC), which was subsequently entrapped in a PVA sponge. Under optimal conditions, good linearities were achieved in the concentration range from 0.8 ng mL−1 to 1.6 µg mL−1 for methylparaben (MP) and from 1.6 ng mL−1 to 1.6 µg mL−1 for ethylparaben (EP), propylparaben (PP), and butylparaben (BP). The limits of detection (LODs) were 560.2 ± 2.1, 642.4 ± 4.2, 611.1 ± 3.7, and 746.8 ± 5.6 pg mL−1 for MP, EP, PP, and BP, respectively. Good sorbent-to-sorbent reproducibility (n = 6, %RSD ≤ 4.0) and precision (n = 6, %RSD < 6.0) were also obtained. Interestingly, the DESs–MCC/PVA sponge can be reused up to five times retaining > 80% of its extraction efficiency. The developed DESs–MCC/PVA sponge was able to determine four parabens in milk, beverages, and tea samples; MP and EP were detected in two beverages and tea samples in the range of 29.0 ± 1.1–38.4 ± 1.3 ng mL−1 and 8.01 ± 0.95–10.6 ± 1.2 ng mL−1, respectively. Good recoveries were obtained in the range of 87.6 ± 3.5%–100.8 ± 4.7% for all the tested parabens in the samples. In conclusion, the development of DESs–MCC entrapped in a PVA sponge is simple and environmentally friendly, affording a reusable DESs–MCC/PVA sponge. Additionally, the DESs–MCC/PVA sponge exhibited good efficiency and is promising for the extraction of various trace organic substances.

Insights into the Superior Bioavailability of Biogenic Sulfur from the View of Its Unique Properties: The Key Role of Trace Organic Substances.

Elemental sulfur (S0) is widely utilized in environmental pollution control, while its low bioavailability has become a bottleneck for S0-based biotechnologies. Biogenic sulfur (bio-S0) has been demonstrated to have superior bioavailability, while little is known about its mechanisms thus far. This study investigated the bioavailability and relevant properties of bio-S0 based on the denitrifying activity of Thiobacillus denitrificans with chemical sulfur (chem-S0) as the control. It was found that the conversion rate and removal efficiency of nitrate in the bio-S0 system were 2.23 and 2.04 times those of the chem-S0 system. Bio-S0 was not pure orthorhombic sulfur [S: 96.88 ± 0.25% (w/w)]. Trace organic substances detected on the bio-S0 surface were revealed to contribute to its hydrophilicity, resulting in better dispersibility in the aqueous liquid. In addition, the adhesion force of T. denitrificans on bio-S0 was 1.54 times that of chem-S0, endowing a higher bacterial adhesion efficiency on the sulfur particle. The weaker intermolecular binding force due to the low crystallinity of bio-S0 led to enhanced cellular uptake by attached bacteria. The mechanisms for the superior bioavailability of bio-S0 were further proposed. This study provides a comprehensive view of the superior bioavailability of bio-S0 and is beneficial to developing high-quality sulfur resources.

Comprehensive Analysis of Organic Micropollutants in Fine Particulate Matter in Hanoi Metropolitan Area, Vietnam

Rapid urbanization has led to increased environmental pollution in Vietnam, especially air pollution issues. In this study, we used gas chromatography-mass spectrometry with an automated identification and quantification system database to detect and quantitate compounds in atmospheric fine particulate matter (PM2.5). A total of 288 compounds classified in 19 pollutant categories based on their origins were detected in PM2.5 samples collected in three areas of Hanoi during winter. The total content of substances detected ranged from 41.08 to 795.00 ng.m−3. The characteristics and concentrations of organic pollutants differed among the industrial, urban, and agricultural sampling areas, with average concentrations of 179.00, 112.10, and 529.40 ng.m−3, respectively. In this comprehensive study on trace organic compounds conducted with samples collected at three sites, we investigating the basic impact of three main factors on the environment. This study contributes to the literature by providing a data set on the content of trace organic substances in the air at the study site.

Water supply safety of riverbank filtration wells under the impact of surface water-groundwater interaction: Evidence from long-term field pumping tests

Water supply safety of riverbank filtration wells (RBFWs) have attracted a great deal of attention in recent years as their role in water supply is increasingly valued. In this study, this issue was revealed from the perspective of water level, quality and supply capacity of RBFWs based on an interference-pumping test with three pumping wells near the Songhua River in Northeast China followed by a recovery test. The results showed that a stable cone of depression of groundwater level in the riverbank filtration (RBF) formed after pumping for about five days with the maximum drawdown of the groundwater level of 10.42 m. The corresponding water capacity of the well group maintained 2.78 × 104 m3/d from then until the end of the test, 60% of which were captured directly from the river. The groundwater level could return to the level before the pumping test after the pumping test stopped for one day. The RBF could provide turbidity, trace organic substances and major cations and anions (except for Ca2+ and Mg2+) pre-treatment of the river water with the removal rates of 29%-95% for some water quality indicators. However, limited improvement of water quality was observed with respect to some inorganic contaminants (Fe, Mn and NH4+-N) because the background concentrations of them in the groundwater were higher than in the river water. When compared with the impact on water level and supply capacity, the impact of the surface water-groundwater interaction on the mechanisms of water quality evolution was more complicated. Taken together, the results of this study indicate that RBFWs can ensure a sustainable water supply of stable quality, which can also simplify the post-treatment processes of waterworks and reduce costs.

Unexpected Aldehyde Generation in the Exhaust Gas at Waste Incineration Facilities.

Acid gases generated during the thermal treatment of waste are neutralized using devices, such as bag filters coated with slaked lime. However, residual trace organic substances can react with the highly reactive slaked lime. This study investigates the dynamics of organic substances generated in the bag filter when slaked lime is used in the exhaust gas treatment process. The mechanism of aldehyde generation was clarified using head space gas chromatography mass spectrometer (HS-GC/MS). Results indicated that methanol was converted to formaldehyde at a conversion ratio of 0.097% and ethanol was converted to acetaldehyde at a conversion ratio of 0.260%. In addition, when amines used as emulsifiers during slaked lime production persisted in the matrix, acetaldehyde formed at a maximum concentration of 121 mg/m3. The simulation method developed in this study can be used for the initial evaluation of aldehydes unexpectedly produced in an incineration treatment facility.

Titanium Dioxide for Biomedical Uses I. The controlled production of nanoparticles by hidrothermal synthesis moderated by dimedone

The controlled the solvo-hydro-thermal titanium dioxide synthesis moderated by dimedone from organometallic precursors is approached in order to obtain nanoparticles compatible with the polymeric systems used in the dental technique. The experiments carried out with relation to the production of titanium dioxide nanoparticles using the solvo-hydro-thermal synthesis allowed the production of three types of materials by means of varying the nature of the used solvent: methanol, ethanol and propanol (TiO2-M, TiO2-E and TiO2-P).The characterisation using electron microscopy (SEM and HRTEM), X-ray analysis, FTIR and UV-Vis spectrometry show that the diameter of the produced nanoparticles is less than 15 nm and decreases in the order: dpMethanol ] dpEthanol ] dpPropanol. The nanoparticles contain trace organic substances which the smaller they are, the bigger the alcohol chain used as a solvent is. The adsorption of a target dye showed increasing values with the increasing number of atoms in the hydrocarbon alcohol chain. The highlighted characteristics suggest the possibility of using the synthesised nanoparticles in the production of hard implants for dental reconstruction.

Source apportionment of trace contaminants in urban sewer catchments

Sampling and analysis of Water Framework Directive priority chemicals were undertaken in nine urban catchments across the UK. Over 9000 samples were collected from a number of different catchment sources including tap water, domestic waste water, surface water runoff, trade discharges, town centre and light industrial estate wastewaters. Determinands included trace metals, polyaromatic hydrocarbons (PAHs), persistent organic pollutants and a number of common pharmaceuticals. Loads of the chemicals from each catchment entering the local wastewater treatment works (WwTW) were estimated and were shown to be relatively consistent between different catchments, after taking population into account. A Monte Carlo mixing model was used to combine the concentrations and flows from the different catchment sources and to predict concentrations and loads entering the WwTW. Based on the model output, the significance of the different sources could be evaluated. The study highlighted the importance of domestic wastewater as a source of contaminants, including metals and trace organic substances (such as ethylenediaminetetraacetic acid (EDTA), bisphenol A, nonylphenol and tributyl tin (TBT)). Concentrations in trade discharges were important in some locations in the case of nonylphenol, EDTA, TBT, as well as for some metals such as copper, zinc and nickel. Contributions to the total load from town centre and light industrial estate sources were generally less than 10% of the total.

Lognormality of trace contaminant concentrations in sewage effluents.

It is important to understand the statistical distribution of monitoring data for them to be of value in determining the parameters of environmental models. No such distributional information has been available for many trace contaminants in sewage effluents. This paper applies the data of a major UK sewage works' effluent monitoring programme to determine the validity of the common assumption that data are lognormally distributed. Effluent quality was monitored at 162 wastewater treatment works over 1year, generating over 3,000 results for each of over 40 substances, including metals, trace organic substances and pharmaceuticals. It is demonstrated that the lognormal assumption is clearly justified for the great majority of substances in the spatial case-for annual average effluent concentrations across different treatment works. In the site-specific, temporal case-for individual determinations of concentration at a single site over an annual period-lognormality is generally supported but not demonstrated so unequivocally for all site/substance combinations. The principal source of uncertainty was lack of sufficient numbers of observations reported to adequately low reporting limits.

Time-Resolved Photoluminescence Spectroscopy and Imaging: New Approaches to the Analysis of Cultural Heritage and Its Degradation

Applications of time-resolved photoluminescence spectroscopy (TRPL) and fluorescence lifetime imaging (FLIM) to the analysis of cultural heritage are presented. Examples range from historic wall paintings and stone sculptures to 20th century iconic design objects. A detailed description of the instrumentation developed and employed for analysis in the laboratory or in situ is given. Both instruments rely on a pulsed laser source coupled to a gated detection system, but differ in the type of information they provide. Applications of FLIM to the analysis of model samples and for the in-situ monitoring of works of art range from the analysis of organic materials and pigments in wall paintings, the detection of trace organic substances on stone sculptures, to the mapping of luminescence in late 19th century paintings. TRPL and FLIM are employed as sensors for the detection of the degradation of design objects made in plastic. Applications and avenues for future research are suggested.

Nanofiltration of river water — fouling, cleaning and micropollutant rejection

Four nanofiltration and low pressure reverse osmosis membranes were investigated concerning their retention and fouling behavior during filtration of a surface water (River Alb) spiked with four polar micropollutants. Filtration and cleaning experiments were also conducted in deionized water spiked with the model contaminants in order to evaluate the influence of the water matrix on retention. Steric and electrostatic effects were found to be the most important factors influencing retention of the organic substances. In the presented experiments, fouling had little influence on retention. In case of the DI water experiments, treatment of the membranes with NaOH solution considerably lowered the retention of the investigated micropollutants, whereas in the experiments with river water the effect of alkaline treatment on the rejection of the trace organic substances decreased to an insignificant amount already 1 h after membrane cleaning.

Thermodynamic Concepts in Modeling Sorption at the Mineral-Water Interface

Sorption phenomena on mineral-water interfaces (MWI) are known to control the retention of many trace elements and organic substances of environmental concern, as well as the kinetics of mineral dissolution/precipitation (Sposito 1984; Davis and Kent 1990; Dzombak and Morel 1990; Goldberg 1992; Stumm 1992; Morel and Hering 1993; Langmuir 1997; Zachara and Westall 1999; Benjamin 2002b; Ganor et al. 2009; and references therein). However, there is still no agreement about a uniform thermodynamic concept which can account for the relevant physicochemical interactions at MWI and can be implemented in popular geochemical modeling codes. This is a major obstacle for compiling a unified (ad)sorption thermodynamic database, also marred by disagreements in defining standard and reference states for (ad)sorbed species. In turn, confusion stems from the multiplicity of thermodynamic concepts used in the description of sorption phenomena on MWIs. The goal of this contribution is to summarize these concepts in a hope to illuminate ways along which they can eventually be made mutually consistent. A minor element (M) can be retained on mineral-water interfaces by a number of sorption mechanisms which also depend on time. On a kinetic basis, this can be summarized in the so-called sorption continuum . At short reaction times, aqueous complexation competes for M with ion exchange on permanently-charged surfaces (such as basal planes or interlayer of clay minerals), as well as the outer-sphere surface complexation on (hydr)oxides. These fast processes are (almost) reversible. At longer reaction times, specific ( multi-site ) adsorption on clay particle edges or (hydr)oxides takes place; this kind of binding into inner-sphere surface species often displays an energetic heterogeneity at low total M concentrations in the system and becomes progressively irreversible with time. At still longer reaction times, the incorporation of (ad)sorbed species deeper into …

Removal of trace organic substances from river bank filtrate – performance study of RO and NF membranes

Producing drinking water from raw waters like river bank filtrate nowadays requires the safe removal of ever new emerging organic substances. At present, in Germany perfluorinated organic compounds are heavily discussed. When it comes to trace organics removal, reverse osmosis (RO) and nanofiltration (NF) are alternatives to conventional bank filtrate treatment technologies like ozonation and activated carbon adsorption. However, the trace organics removal capabilities of dense membranes are still under investigation. Questions about concentrate disposal strategies are still open. The paper presents results from lab-scale and pilot studies which were conducted for the project planning of a 1,100 m3/h NF plant treating river Rhine bank filtrate. Membranes from loose NF to dense RO were investigated spiking the raw waters with trace organic substances which usually pass the soil passage and to some extent even the conventional treatment process. The results showed high retention capabilities of the more dense membranes, even under ageing conditions.

Leachate quality from landfilled MBT waste

A research project recently completed on behalf of the UK Environment Agency, has collected data and sampled leachates from EU landfills that have received imports of MSOR and MBT wastes. Results are presented for sanitary analyses, heavy metals, and an extensive range of trace organic substances, from sites containing MBT wastes that have received different degrees of composting pre-treatment. Leachates produced from MSOR wastes have a very high polluting potential, but biological pre-treatment of these wastes can avoid the peak acetogenic phase of decomposition, and produce leachates similar to, or weaker than, those from conventional methanogenic landfills. Effective MBT processes can also significantly reduce concentrations of trace organics, and of ammoniacal-N in leachates. However, further research is needed to examine the relative importance of nitrification/denitrification processes, generation of stable, organically based nitrogen forms, and other routes during MBT processing, in order that appropriate reactions to remove nitrogen can be encouraged and optimised.

Henry's law constants measurements of the nonylphenol isomer 4(3′,5′-dimethyl-3′-heptyl)-phenol, tertiary octylphenol and γ-hexachlorocyclohexane between 278 and 298 K

Abstract Henry's Law Constants (HLC, M atm−1) were determined for the diastereomeric mixture of the nonylphenol isomer 4(3′,5′-dimethyl-3′-heptyl)-phenol diastereomers (NP353(+) and NP353(−)), tertiary octylphenol (t-OP) and γ-hexachlorocyclohexane (γ-HCH) in artificial seawater over a temperature range 278–298 K using a dynamic equilibrium system. Trace organic substances present in the gas phase were trapped by tandem XAD-2 cartridges and extracted with a soxhlet extractor. The extracts were derivatived with N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA), and then analyzed with GC-MS in the selective ion mode. At 293 K and in artificial seawater, HLC (M atm−1) were found to be equal to: NP353(+), HLC=(483±169); NP353(−), HLC=(551±193); t-OP, HLC=(400±140); γ-HCH, HLC=(876±307). The obtained data were used to derive the following Van’t Hoff expressions: ln HLC (NP353(+))=8.73 (±0.95)×(1000/T) –23.61 (±3.30); ln HLC (NP353(–))=8.61 (±0.91)×(1000/T)−23.08 (±3.18); ln HLC (t-OP)=9.03 (±1.40)×(1000/T)−24.83 (±4.86); ln HLC (γ-HCH)=6.17 (±1.08)×(1000/T)−14.28 (±3.75). The derived enthalpies of solvation for NP353(+), NP353(−), t-OP and γ-HCH are −72.6±7.9, −71.6±7.6, −75.1±11.5 and −51.3±9.0 kJ mol−1, respectively. The HLC measurements of γ-HCH, which was used as reference substance, were in good agreement with literature values and its corresponding derived enthalpy of solvation agrees well to the previous values reported in the literature. A reassessment of the air/water gas exchange based on experimentally derived HLC was made for the nonylphenol (NP) in the Lower Hudson River estuary (New York/New Jersey, USA) that was previously reported by Van Ry. A net atmospheric deposition was calculated for the gas exchange of NP in the Lower Bay (Ffw=0.13), and it nearly reaches the condition of equilibrium in the Upper Bay (Ffw=0.46).

Removing aquatic organic substances by anion-exchange resin and activated carbon

The purpose of this study was to compare the adsorption characteristics of trace organic substances (TOC) from a drinking water supply between synthetic resin and granular activated carbon (GAC). In batch experiments, the effect of dosage and pH showed that the resin is much better than GAC, and a lower temperature favors an increased capacity of resin and GAC. A comparison of four adsorption models showed that the order of square of correlation coefficient for each model on resin and GAC was the same and the order was linear, Freundlich, Langmuir, and Brunauer-Emmett-Teller (BET) from high to low. In the single-column study, resin had 1.6–6.0 times the breakthrough time of GAC and the breakthrough volumes of resin were 1.5–5.8 times that of GAC. The four serial columns study showed that the adsorption capacity for TOC by resin was 1.40 g/L and approximately up to 15 times greater than by GAC. The service time of resin was higher than that of GAC by a factor of 6–22, and the treated volumes were also 4–13 times that of GAC's. The resin was more effective than GAC after a proper selection in a traced TOC removal.

Stability of trace organic substances in water: data obtained from interlaboratory tests

Evidence is presented on the stability of drinking water samples for the determination of trihalomethanes, volatile solvents and polynuclear aromatic hydrocarbons. Data from interlaboratory tests suggest that trihalomethanes and solvents at concentrations in the range 1–100 µg l–1 are not subject to changes in concentration of more than 15% over several weeks. Similar tests indicate serious losses of polynuclear aromatic hydrocarbons from spiked water samples. This is attributed to adsorptive losses of the determinands to the sample container.

Determination of isoprene in human breath by thermal desorption gas chromatography with ultraviolet detection

We describe a new, highly sensitive and specific method for the analysis of isoprene (2-methyl-1,3-butadiene) in human breath. A known volume of expired air (150 ml) was drawn through a solid sorbent material to capture trace organic substances, followed by thermal desorption at 200°C and subsequent determination of isoprene by gas chromatography with diode-array ultraviolet detection. The calibration plot was linear ( r = 0.99) over a wide range of breath isoprene concentrations (0–12 nmol/l), and levels down to 0.10 nmol/l were easily measurable. In sixteen healthy subjects (six men and ten women), all of whom were non-smokers, the mean, median and spread of breath isoprene concentrations were 3.73, 3.36 and 1.60–10.33 nmol/l, respectively. No statistically significant differences in the concentrations of breath isoprene were observed between the sexes. The mean (± S.D.) concentration of breath isoprene in nine consecutive tests with the same subject was 3.69±0.60 nmol/l, and the coefficient of variation was 16.3%. Much larger variations in exhaled isoprene were seen during the day and also between days when the same subject was tested repeatedly. The excretion patterns of isoprene in human breath can be investigated with high selectivity and sensitivity with this new analytical method.

Classroom determination of trace organic substances by catalytic methods

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTClassroom determination of trace organic substances by catalytic methodsHelmut Wenck , Grit Kruska , Ranier Lohrie , and Ekkehard Diemann Cite this: J. Chem. Educ. 1988, 65, 7, 633Publication Date (Print):July 1, 1988Publication History Received3 August 2009Published online1 July 1988Published inissue 1 July 1988https://doi.org/10.1021/ed065p633RIGHTS & PERMISSIONSArticle Views56Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1007 KB) Get e-Alerts Get e-Alerts