Industrial Organic Pollutants Research Articles

Electrical impedance sensing of organic pollutants with ultrathin graphitic membranes

In this paper we propose an original approach for the real-time detection of industrial organic pollutants in water. It is based on the monitoring of the time evolution of the electrical impedance of low-cost graphitic nanomembranes. The developed approach exploits the high sensitivity of the impedance of 2D graphene-related materials to the adsorbents. We examined sensitivity of the nanomembranes based on pyrolyzed photoresist, pyrolytic carbon (PyC), and multilayer graphene films. In order to realize a prototype of a sensor capable of monitoring the pollutants in water, the membranes were integrated into an ad hoc printed circuit board. We demonstrated the correlation between the sensitivity of the electric impedance to adsorbents and the structure of the nanomembranes, and revealed that the amorphous PyC, being most homogeneous and adhesive to the SiO2 substrate, is the most promising in terms of integration into industrial pollutants sensors.

Ethyl chloroformate mediated gas chromatographic-mass spectrometric biomonitoring of acidic biomarkers of occupational exposure and endogenous metabolites in human urine

Numerous industrial organic pollutants such as aromates, alkoxyalcohols, other organic solvents and monomers are absorbed, metabolized, and finally excreted in urine mostly as carboxylic acids that are determined as biomarkers of exposure. For a number of these xenometabolites, biological limits (levels of biomarkers in biological material) have been established to prevent damage to human health. Till now, most of the analytical procedures used have been optimized for one or a few analytes. Here, we report a more comprehensive approach enabling rapid GC-MS screening of sixteen acidic biomarkers in urine that are metabolized in the human body from several important industrial chemicals; benzene, toluene, styrene, xylenes, alkoxyalcohols, carbon disulfide, furfural and N,N-dimethylformamide. The new method involves immediate in situ derivatization – liquid liquid microextraction of urine by an ethyl chloroformate-ethanol-chloroform-pyridine medium and GC-MS analysis of the derivatized analytes in the lower organic phase. The xenometabolite set represents diverse chemical structures and some of hippuric and mercapturic acids also provided unusual derivatives that were unambiguously elucidated by means of new ethyl chloroformates labeled with stable isotopes and by synthesis of the missing reference standards. In the next step, an automated routine was developed for GC-MS/MS analysis using a MetaboAuto® sample preparation workstation and the new method was validated for fourteen metabolites over the relevant concentration range of each analyte in the spiked pooled human urine. It shows good linearity (R2 ≥ 0.982), accuracy (from 85% to 120%), precision (from 0.7% to 20%) and recovery (from 89% to 120%). The method performance was further successfully proved by GC-MS/MS analysis of the certified IP45 and RM6009 reference urines. Moreover, we show that the new method opens up the possibility for biomonitoring of combined and cumulative occupational exposures as well as for urinary metabolite profiling of persons exposed to harmful industrial chemicals.

Tetradecylamine-MXene functionalized melamine sponge for effective oil/water separation and selective oil adsorption

In recent years, oil spills and industrial organic pollutants have caused irreparable damage to the environment and biological ecosystems. Therefore, the treatment of oily wastewater has become a serious global challenge. Here, we prepared superhydrophobic and superoleophilic tetradecylamine-MXene functionalized melamine sponge for effective oil/water separation and selective oil adsorption using a facile and effective method. It is found that the functionalized sponge can selectively and effectively absorb various oils from oil/water mixtures, which absorption capacity ranges from 60 to 112 times its own mass. Moreover, the water-in-oil emulsion can be efficiently separated by the functionalized sponge, due to its high oil selectivity. Besides, the functionalized sponge shows great mechanical property, chemical stability, and repeatability in various harsh environments, which make it great promising in the treatment of oily wastewater.

Mechanism of destruction of Quercus robur and Betula pendula leaves by exposure of organic pollutants

Exposure of industrial pollutants including styrene, formaldehyde, acetone in the concentration range of maximal permissible concentration of working zone on leaves of silver birch (Betula pendula) and English oak (Quercus robur) chosen as model objects were studied and a mechanism of degradation was proposed. At a macroscopic level an indicator role of the leaf pattern for industrial organic pollutants with various functional groups was established. The differentiated effect of biotoxicants revealed selectivity of chemical reactions and appearance of various products of these reactions on the surfaces of the leaf blade. For all studied objects, systemic IR spectroscopic studies of cuts from oak and birch leaves were carried out. The characteristic frequencies testifying to interaction of pollutants with leaf tissue have been identified. The criteria for the control of tree plantations have been proposed, manifesting in a combination of two methods: at the macroscopic level, by establishing the indicator role of the pattern, and at the molecular level, by IR spectroscopic determination of chemical interaction in the system "functional groups of biotoxicants - leaf blade". The studies carried out make it possible to create a database of industrial pollutants and propose interrelated criteria for monitoring tree plantations.

Fruit rinds extracted cellulose and its utility in fabricating visible light tin sulfide photocatalyst for the treatment of dye, pharmaceutical and textile effluents

Fruit rinds isolated cellulose supported 2D tin sulfide nanostructures have been developed for the improved photodegradation of the standard and industrial organic pollutants. Some industrial organic pollutants are so persistent that they bioaccumulate in animal tissues and biomagnify along food chains adversely affecting humans, wildlife and the environment. For minimizing the cost of photocatalyst, extraction of cellulose was carried out from waste fruits peels (pomegranate, orange, sweet lime and banana) by simple chemical route which later was lyophilized to attain a nontoxic and economic support. These cellulose/tin sulphide photocatalysts were used to study the photocatalytic activity of Rhodamine B dye as standard as well as real sample analysis of industrial pharmaceutical and textile effluents. In all cellulose/tin sulfide nanocomposites, the greatest photocatalytic activity was attained where cellulose was in optimum amount (500 mg). The maximum rate was found to be ∼0.087 min−1 which was ∼20 times higher than the pristine tin sulfide nanostructures. For the quenching studies and photo stability issues of the photocatalyst, scavenging and recyclability tests were performed respectively. The improvement in an average lifetime from 72 to 123 ns showed that the photocatalytic activity increased with the effect of the cellulose support. This nanoscale photocatalyst would be beneficial for the humans as they don’t generate secondary contaminants unlike other methods and are also valuable for waste water treatment.

A laser metallurgy route for the batch preparation of mm-scale 3D silver/graphite heteronanoclusters in air.

We report a batch preparation of mm-scale 3D Ag hetero-nanoclusters which exhibit an excellent surface plasmon resonance ability via facile laser metallurgy. Under laser irradiation, the porous AgI-based coordination network crystals were instantly converted into 3D graphite-encapsulated Ag hetero-nanoclusters with uniform sizes and gaps in several seconds. The obtained hetero-nanoclusters exhibited superior 3D confocal laser energy utilization compared with the other 0D, 1D and 2D SERS substrates, solving the bottleneck caused by laser focusing deviation in the SERS active depth. The mass-produced SERS devices were ultra-sensitive for the detection of life and industrial organic pollutants in terms of low detection and enriched capacity.

Photodecontamination of Vat Green 1 and Dianix Blue dyes by MWCNTs/x%TiO2 nanocomposites synthesized using evaporation method

Study of the photocatalytic activity of multi-walled carbon nanotubes/titanium dioxide nanocomposites MWCNTs/x%TiO2 with different weight ratios of TiO2 (x = 3, 6 and 10%) synthesized using a simple modified evaporation method in decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories was reported. The structure of the synthesized MWCNTs and MWCNTs/x%TiO2 nanocomposites with different weight ratios photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic technique and N2 adsorption-desorption. Also optical band gap was estimated by Kubelka-Munk equation for MWCNTs and MWCNTs/x%TiO2 nanocomposites giving rise values 3.51, 2.89, 2.80, 2.69 eV respectively. The photodegradation of Vat Green 1 and Dianix Blue Dyes dyes in presence of MWCNTs and MWCNTs/x%TiO2 nanocomposites after complete degradation were measured using chemical oxygen demand processes and the suggested possible mechanism of the photodegradation processes of Vat Green 1 and Dianix Blue Dyes was studied.

Adsorption mechanism of phenol, p-chlorophenol, and p-nitrophenol on magnetite surface: A molecular dynamics study

Industrial wastewater organic pollutants like phenol can either be treated by a catalytic oxidation process or by adsorption on active surfaces. In this context, the understanding of the mechanism of adsorption on easily recoverable magnetic adsorbents is an important requirement for further progress in this area. The present study employs canonical ensemble molecular dynamics simulations to gain a better understanding of the adsorption mechanism of the organic pollutants phenol (Ph), p-chlorophenol (PCP) and p-nitrophenol (PNP) present in water on (111) magnetite surface. Systems with varying concentrations of these molecules in water were considered. Simulations generated equilibrium density profiles of adsorbed molecules on the (111) magnetite surface. The density profiles at various adsorbate concentrations were used to generate adsorption isotherms. It was found that data generated for all three organic molecules fitted best the non-linear Freundlich isotherm. Adsorption constant for PCP is found to be greater than those of PNP and Ph. The order of adsorption energies is in agreement with this. Functional groups involved in absorbate-adsorbent interaction have been identified by radial distribution function analysis.

Sodium silicate based aerogel for absorbing oil from water: the impact of surface energy on the oil/water separation

Industrial organic pollutants and oily wastewater are becoming a serious worldwide problem that are threatening the environments. Silica aerogels with hydrophobicity and oleophilicity have a significant potential to develop their use as an oil absorption and can be used to absorb different oils emulsion. Herein, inspired by lotus leaves and gecko toes, we fabricate superhydrophobic and superoleophilic silica aerogel from inexpensive sodium silicate precursors by a facile sol-gel method followed by the low-cost ambient drying process. The microstructural properties of the silica aerogel are investigated by TEM and BET analysis. The resulted aerogels are ultra-lightweight (0.23 g cm−3) and highly porous (90%) with a pore distribution of 24 nm. Furthermore, oleophilic–hydrophobic characteristics of silica aerogel are investigated by the chemical structure and the surface energy of the silica aerogel using solid-state NMR, FTIR and also measuring the water/alcohol contact angle, sliding angle and oil spill absorption. Silica aerogel shows superior water repellency with the contact angle of 150°, super oleophilicity to different oils, outstanding absorption capacity for oils (up to 4 g of oil/g of aerogel), and eminent absorption recyclability (100%, even after 10 cycles). Due to its low density, lightweight, superhydrophobicity, low-cost materials, and considerable oil absorption properties, we expected that silica aerogel can be used for oil-spill cleanup. Besides, we establish the relationship between surface energy and water/oil contact angle to understand the mechanisms that occur during the oil/water separation process.

Capillarity-driven both light and heavy oil/water separation via combined system of opposite superwetting meshes

To better circumvent the issues of oil spills and industrial organic pollutants, it is urgent and necessary to develop advanced material or technology that can efficiently separate oil/water mixture. Herein, no matter light or heavy oil/water mixtures are separated successfully by a straight tee system combining two opposite superwetting meshes. The combined system shows a high flux (above 0.22 × 105 L m−2 h−1), high efficiency (above 99.3%) for continuous light or heavy oil/water separation with good durability. Importantly, the superhydrophilic and superhydrophobic meshes can be easily obtained via facile, viable electroless galvanic replacement reaction followed post surface modification strategy. Additionally, the capillary action was used to clarify mechanism of oil/water separation to gain insight into oil/water separation process. The merits of high flux, high efficiency, viable for light/heavy oil and durability make this separation system a powerful tool for practical application in continuous oil/water separation.

Metal-Oxide-Based Microjets for the Simultaneous Removal of Organic Pollutants and Heavy Metals.

Water contamination from industrial and anthropogenic activities is nowadays a major issue in many countries worldwide. To address this problem, efficient water treatment technologies are required. Recent efforts have focused on the development of self-propelled micromotors that provide enhanced micromixing and mass transfer by the transportation of reactive species, resulting in higher decontamination rates. However, a real application of these micromotors is still limited due to the high cost associated to their fabrication process. Here, we present Fe2O3-decorated SiO2/MnO2 microjets for the simultaneous removal of industrial organic pollutants and heavy metals present in wastewater. These microjets were synthesized by low-cost and scalable methods. They exhibit an average speed of 485 ± 32 μm s-1 (∼28 body length per s) at 7% H2O2, which is the highest reported for MnO2-based tubular micromotors. Furthermore, the photocatalytic and adsorbent properties of the microjets enable the efficient degradation of organic pollutants, such as tetracycline and rhodamine B under visible light irradiation, as well as the removal of heavy metal ions, such as Cd2+ and Pb2+.

Occurrence and risk assessment of potentially toxic elements and typical organic pollutants in contaminated rural soils

The residual levels and risk assessment of several potentially toxic elements (PTEs), phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) in rural soils near different types of pollution sources in Tianjin, China, were studied. The soils were found to be polluted to different extents with PTEs, PAEs and PAHs from different pollution sources. The soil concentrations of chromium (Cr), nickel (Ni), di-n-butyl phthalate (DnBP), acenaphthylene (Any) and acenaphthene (Ane) were higher than their corresponding regulatory reference limits. The health risk assessment model used to calculate human exposure indicates that both non-carcinogenic and carcinogenic risks from selected pollutants were generally acceptable or close to acceptable. Different types of pollution sources and soil physicochemical properties substantially affected the soil residual concentrations of and risks from these pollutants. PTEs in soils collected from agricultural lands around industrial and residential areas and organic pollutants (PAEs and PAHs) in soils collected from agricultural areas around livestock breeding were higher than those from other types of pollution sources and merit long-term monitoring.

Carbon nanotubes-ferrite-manganese dioxide micromotors for advanced oxidation processes in water treatment

Multifunctional SW-Fe2O3/MnO2 tubular micromotors are used for ‘on-the-fly’ advanced water oxidation of industrial organic pollutants.

Passive air sampling of polybrominated diphenyl ethers in New Delhi, Kolkata, Mumbai and Chennai: Levels, homologous profiling and source apportionment

Several studies in the recent past reported new sources for industrial persistent organic pollutants (POPs) from metropolitan cities of India. To fill the data gap for atmospheric polybrominated diphenyl ethers (PBDEs), polyurethane foam disk passive air sampling (PUF-PAS) was conducted along urban-suburban-rural transects in four quadrilateral cities viz., New Delhi, Kolkata, Mumbai and Chennai from northern, eastern, western and southern India respectively. Average concentration of Σ8PBDEs in pg/m3 for New Delhi, Kolkata, Mumbai and Chennai were 198, 135, 264 and 144 respectively. We observed a distinct urban > suburban > rural trend for atmospheric PBDEs in Mumbai. Principal component analysis (PCA) attributed three different source types. BDE-47, -99, −100, −153 and −154 loaded in the first component were relatively high in the sites where industrial and informal electronic waste (e-waste) recycling activities were prevalent. Penta congener, BDE-99 and tetra congener, BDE-47 contributed 50%–75% of total PBDEs. Ratio of BDE-47 and -99 in Indian cities reflected the usage of penta formulations like Bromkal −70DE and DE-71 in the commercial and electrical products. PC-2 was loaded with BDE-28 and -35. Percentage of BDE-28 and BDE-35 (>10%) were comparatively much higher than commercial penta products. Abundance of BDE-28 in majority sites can be primarily due to re-emission from surface soil. PC-3 was loaded with BDE-183 and elevated levels were observed mostly in the industrial corridor of Indian cities. BDE-183 was notably high in the urban industrial sites of New Delhi. We suspect this octa-BDE congener resulted from recycling process of plastic products containing octa-BDE formulation used as flame retardants.

Blue and violet defect levels mediated absorption hot spots in tapered ZnO nanorods toward improved photocatalytic activity

Tapered ZnO nanorods have been synthesized and found to have efficient photocatalytic properties owing to a large number of native defect sites arising from oxygen non-stoichiometry. The estimation of defect states was carried out using photoluminescence spectroscopy. Visible light-driven photocatalytic activity of the prepared ZnO nanorods was evaluated by measuring the photodegradation of two widely used industrial organic pollutants, viz. rose bengal and methylene blue. Investigation of electric field profile of the tapered ZnO nanorods revealed the generation of huge absorption hot spots in the visible region, indicating better light trapping in tapered ZnO nanorods than the non-tapered structure.

Intermolecular mechanistic treatment of recalcitrant environmental pollutants: Azo, benzene, naphthalene and vinyl sulfone

Abstract A new class of coagulant, from natural resource namely laterite soil has demonstrated efficiency in degrading a wide range of industrial organic pollutants into simple hydrocarbon structures or less toxic compounds. The composition study revealed the relative Si/Al/Fe: 0.57/0.33/0.10 ratios in laterite soil and surface morphology of laterite soil were investigated to analyze the fundamental degradation that drive the decolorization of Reactive Black 5 (RB 5). The interfacial and colloid aspects of laterite soil colloidosomes and dye particles were distinguished with the corresponding mechanism of coagulation–flocculation process. RB5 structure was destabilized by activation of laterite soil colloidosomes through charge neutralization and subsequent siloxane polymerization through enhancement of siloxanes monomers. This research also evaluated the rate laws and reaction mechanism for each of the main chemical network strands of RB 5. The result implied that all the chemical network strands followed the pseudo first order of reactions. Research approach has utilized Fourier Transform Infrared Spectroscopy, Gas Chromatography Mass Spectrometry and Ultraviolet–visible Spectrophotometry (FTIR, GCMS and UV–vis) to study the degradation intermediates structure, chemical derivatives and final products after coagulation–flocculation process.

Facile Fabrication of a Polyethylene Mesh for Oil/Water Separation in a Complex Environment.

Low cost, eco-friendly, and easily scaled-up processes are needed to fabricate efficient oil/water separation materials, especially those useful in harsh environments such as highly acidic, alkaline, and salty environments, to deal with serious oil spills and industrial organic pollutants. Herein, a highly efficient oil/water separation mesh with durable chemical stability was fabricated by simply scratching and pricking a conventional polyethylene (PE) film. Multiscaled morphologies were obtained by this scratching and pricking process and provided the mesh with a special wettability performance termed superhydrophobicity, superoleophilicity, and low water adhesion, while the inert chemical properties of PE delivered chemical etching resistance to the fabricated mesh. In addition to a highly efficient oil/corrosive liquid separation, the fabricated PE mesh was also reusable and exhibited ultrafast oil/water separation solely by gravity. The easy operation, chemical durability, reusability, and efficiency of the novel PE mesh give it high potential for use in industrial and consumer applications.

Seasonal and rainfall-type variations in inorganic ions and dicarboxylic acids and acidity of wet deposition samples collected from subtropical East Asia

Rainfall samples were collected over a period of 3 years and 8 months in subtropical East Asia. They are categorized into different rainfall types and analyzed to assess the ionic composition and its effect on the acidity of wet deposition in southern Taiwan. Only 4% of samples had a pH of <5.0, indicating that the study area is not impacted significantly by acid rain. The volume-weighted mean (VWM) pH by rainfall type was Spring Rain 5.74, Typhoon Rain 5.56, Summer Rain 5.46, Typhoon Outer Circulation (TOC) Rain 5.45, Plum Rain 5.32 and Autumn–Winter Rain 5.29. Dilution effects were important to the equivalent ionic concentration of different rainfall types. HCO3−, SO42− and Cl− were detected as major anions whereas NH4+, Na+ and Ca2+ were major cations. CO2-derived HCO3− was the major ionic species in all but Typhoon Rain and Spring Rain, in which the major species were Na+ and Cl− and Ca2+, respectively. Excluding HCO3−, the major species were NH4+, Na+ and Ca2+ in Plum Rain, the secondary photochemical products SO42−, NO3− and NH4+ in TOC Rain and Summer Rain, and Na+ and Ca2+ in Autumn–Winter Rain. Calculation of arithmetic means showed that dicarboxylic acids contributed between 0.25% and 0.53% of the total ionic concentration and of these, oxalic acid contributed the least (81.3% of the dicarboxylic acid) to TOC Rain and the most (96.1% of the dicarboxylic acid) to Spring Rain, suggestive of long-range transport in the latter. Differences in wet deposition composition were shown to be a result of differences in local emissions and long-range transport (hence of prevailing wind direction) during the period of rainfall and of the frequency and volume of rain that typifies each rainfall type. Principal component analysis (PCA) further revealed that traffic-related and industrial organic and inorganic pollutants, their secondary photochemical products, sea salts, and dust are important contributors to wet deposition. Moreover, the ratio of malonic acid to succinic acid (M:S ratio) indicated that both traffic and secondary photochemical reactions are major contributors to all but TOC Rain, for which the M:S ratio of 4.54 indicates a relative abundance of pollutants from secondary photochemical reactions. An ion balance (IB) ratio analysis demonstrated the validity of the results in this research.

Emerging food contaminants: a review

Governments throughout the world are intensifying their efforts to improve food safety. These efforts come as a response to an increasing number of food-safety problems and increasing consumer concerns. In addition, the variety of toxic residues in food is continuously increasing as a consequence of industrial development, new agricultural practices, environmental pollution, and climate change. This paper reviews a selection of emerging contaminants in food, including the industrial organic pollutants perfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs), and nanomaterials; the pharmaceutical residues antibiotics and coccidiostats; and emerging groups of marine biotoxins. The main analytical approaches for their detection and quantification in food will be presented and discussed with special emphasis on biological techniques, when these are feasible. In the last section, a summary of recent publications reporting the concentrations of these compounds in food will be presented and discussed.

Fundamentals and applications of the photocatalytic treatment for the removal of industrial organic pollutants and effects of operational parameters: A review

Photocatalysis process, as an environmental application, is a relatively novel subject with tremendous potential in the near future. A number of studies determine the economic viability of applying various ultraviolet advanced oxidation processes for the purpose of degradation and destroying of various pollutant solutions. The present paper reviews the treatment of hazardous wastewater bearing organic compounds and the effects of various parameters such as pH, initial concentration, mass of catalyst, wavelength, light intensity, electron acceptor, temperature, etc., with the treatment cost for different reactor type. This study investigates the effect of various types of waste-water treatment parameters and the treatment cost for various designs of photocatalytic reactors, using both solar and artificial light, have been proposed for their different types of pollutants.