Academia.eduAcademia.edu

Outline

Title
Abstract
Introduction
Methods and Materials
Results
Results of Column Experiments
Discussion and Conclusion
References
All Topics
Chemistry
Chemicals and Drugs

Removal of aqueous-phase polynuclear aromatic hydrocarbons using aspen wood fibers

Profile image of Thomas BovingThomas Boving

2004, Chemosphere

https://doi.org/10.1016/J.CHEMOSPHERE.2003.07.007
visibility

…

description

9 pages

link

1 file

Abstract

Roadway runoff derived polynuclear aromatic hydrocarbons (PAHs) impact the quality of surface and ground water. Inexpensive aspen wood fibers have been investigated as a means to remove dissolved PAH under laboratory conditions. Our isotherm experiments demonstrated that the uptake of naphthalene, fluorene, anthracene, and pyrene required up to 12.5 days to reach equilibrium. Aspen wood-water sorption coefficients, K ww , were linearly correlated to octanol-water partition coefficients and the molecular weight of the studied PAH compounds. The correlation between K ww and molecular weight was the most significant. Column experiments were carried out to study the sorption and desorption of fluorene, anthracene, and pyrene under dynamic conditions. The results indicate linear sorption, but nonlinear desorption behavior. The degree of desorption was inversely correlated to a compound's hydrophobicity. Flow interruption experiments showed that sorption and desorption was rate limited. A mass balance of the sorption and desorption tests indicated that sorptive uptake exceeded desorptive release over a given number of pore volumes. Further, absolute mass-removal efficiency increased with the molecular weight and hydrophobicity of the PAH compound. Batch and column studies demonstrated that aspen wood has the potential to become an effective remedial agent for PAH in stormwater runoff or other PAH contaminated waters.

Related papers

Sorption kinetics of naphthalene and phenanthrene in loess soils
Ronny Berndtsson

Environmental Geology, 2005

View PDFchevron_right
PAHs Sorption and Desorption on Soil Influenced by Pine Needle Litter-Derived Dissolved Organic Matter
Rong-Liang Qiu

Pedosphere, 2014

Study of the relationship between plant litter-derived dissolved organic matter (DOM) and organic pollutant transport in soil is important for understanding the role of forest litter carbon cycling in influencing pollutant behaviour and fate in forest soil. With the aim of providing insight into the capacity of plant litter-derived DOM to influence sorption and desorption of selected polycyclic aromatic hydrocarbons (PAHs) on soil, batch experiments were carried out with application of a sorption-desorption model incorporating DOM effects. Freshly fallen pine (Pinus elliottii) needles were used as the source of organic matter. Input of the pine needle litter-derived DOM was found to significantly decrease desorption hysteresis as well as soil adsorption capacity of phenanthrene (PHE) and fluoranthene (FLA). Addition of 1 728 mg L −1 dissolved organic carbon (DOC) lowered the organic carbon-normalized sorption distribution coefficient of PHE from 7 776 to 2 541 L kg −1 C and of FLA from 11 503 to 4 368 L kg −1 C. Decreases of the apparent sorption-desorption distribution coefficients of PHE and FLA with increased DOC concentration indicated that DOM favored desorption of PAHs from soil. Increases in the fraction of apparently dissolved PAHs were attributable to the dissolved PAH-DOM complexes, accounting for the dissolved proportions of 39% to 69% for PHE and 26% to 72% for FLA in the sorption and desorption processes as the concentration of the added DOM solution rose from 0 to 1 728 mg L −1 . Our results suggest that pine needle litterderived DOM can have a substantial effect of inhibiting PAHs sorption and promoting PAHs desorption, thus leading to enhanced leaching in soil, which should be taken into account in risk assessment of PAHs accumulated in forest soil.

View PDFchevron_right
Desorption of polycyclic aromatic hydrocarbons from soil in the presence of dissolved organic matter: Effect of solution composition and aging
Ingrid Kögel-Knabner

The kinetics of the thermal desorption of a set of three-to five-ring polycyclic aromatic hydrocarbons (PAHs) from a laboratory-generated kerosene soot surface was studied over the temperature range 250-355 K in a low-pressure flow reactor combined with an electron-impact mass spectrometer. Two methods were used to measure the desorption rate constants: monitoring of the surface-bound PAH decays due to desorption using off-line HPLC measurements of their concentrations in soot samples and monitoring of the desorbed molecules (anthracene and phenanthtrene) in the gas phase using in situ mass spectrometric detection. The Arrhenius parameters (A factors and activation energies) for the desorption rate constants of 10 soot-bound PAHs were determined. The PAH-soot binding energies were found to be similar for PAHs with the same number of carbon atoms and to increase with increasing number of PAH carbon atoms. The experimental data are discussed in the frame of the existing theoretical gas to particle partitioning model.

View PDFchevron_right
Remediation of polycyclic aromatic hydrocarbons
Fung-Hwa Chi

CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2011

Hydrocarbon pollution is a threat to the agricultural industry and the natural environment. Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants known for their carcinogenesis, teratogenesis and mutagenesis, making them harmful to humans and the ecological environment. This review paper critically assesses the environmental contamination issues associated with PAHs, with particular attention given to surface waters. An overview of the transport and transformation behaviours of various types of PAHs within surface waters, including the exchange between water and air, photodegradation, adsorption-desorption on particles, uptake by plants and biodegradation is given. Recent findings in areas such as phytoremediation and microbial degradation processes, which are relevant to agriculture, water resources management and environmental science, are highlighted. Finally, the paper recommends further research on the mechanisms of PAHs sorption to particles, and...

View PDFchevron_right
Adsorption and Desorption Kinetics of Naphthalene, Anthracene, and Pyrene in Soil Matrix
Alfred Susu

Petroleum Science and Technology, 2010

The adsorption and desorption kinetics of naphthalene, anthracene, and pyrene in a soil slurry reactor at ambient conditions have been investigated to ascertain the mechanisms controlling the retention and release rates of these compounds in the soil matrix. A stirred-flow method was employed to perform the experiments. The extent of partitioning for the polycyclic aromatic hydrocarbons (PAHs) tested was found to be dependent on their solubility and diffusivity in the aqueous phase. Apparent adsorption and desorption rate coefficients were determined using the Langmuir and Freundlich isotherm models. Equilibrium adsorption and desorption at the external surface and in the internal pore of the soil particle obeyed the Freundlich isotherm equation. The pseudo-equilibrium condition established at the minimum contact time suggests that equilibrium adsorption attained for the contaminant PAHs was not instantaneous but rather time dependent.

View PDFchevron_right
Sorption of Polycyclic Aromatic Hydrocarbons and Polychlorinated Biphenyls to Soot and Soot-like Materials in the Aqueous Environment:  Mechanistic Considerations
Ingrid Kögel-Knabner

Environmental Science & Technology, 2002

View PDFchevron_right
Equilibrium and Kinetic Studies of Sorption of Polycyclic Aromatic Hydrocarbons from Water Using Rice Husk Activated Carbon
Lupong Kaewsichan

Asian Journal of Chemistry, 2013

Sorption studies were carried out to investigate removal of 2.4-dichlorophenol (2.4-DCP) from aqueous solution in a fl uidized bed by two types of adsorbent mixtures: BC (Bamboo char plus Calcium sulphate), and HBC (Hydroxyapatite plus Bamboo char plus Calcium sulphate); both manufactured in ball shape. The main material bamboo char was characterized by FTIR, DTA and SEM. The adsorption experiments were conducted in a fl uidized bed circulation column. Adsorption, isotherms and kinetic studies were established under 180 min operating process time, at different initial 2.4-DCP solution concentrations ranging from 5-10 mg/L, and at different fl ow rates ranging from 0.25-0.75 L/min. The data obtained fi tted well for both the Langmuir and Freundlich isotherm models; indicating favorable condition of monolayer adsorption. The kinetics of both adsorbents complies with the pseudo second-order kinetic model. BC was proven a new effective composite and low cost adsorbent which can be applied in the fi eld of wastewater treatment, and it can also play an important role in industry water treatment.

View PDFchevron_right
Removal of polycyclic aromatic hydrocarbons from organic solvents by ashes wastes
Elena Martínez-Carballo

Journal of Hazardous Materials, 2010

The presence of polycyclic aromatic hydrocarbons (PAHs) in sediments is a major concern of risks associated with the aquatic ecosystems through bioaccumulation in food chains. To minimize the ecological risks due to contaminated sediments, processes that can degrade the sorbed PAHs are urgently needed. The present study aims at assessing the treatment efficiency of several chemical oxidation processes using potassium permanganate (KMnO 4), sodium persulfate (Na 2 S 2 O 8), conventional Fenton, and modified Fenton. Efforts were focused on identifying the most effective liquid oxidant to obtain the maximum acceptable concentration for a total of 16 PAH compounds (1000 ng/g) and on assessing the optimal reactant doses. The concentration of PAHs in the untreated sediment was around 4226 ng/g (2-ring at 273 ng/g, 3-ring at 1285 ng/g, 4-ring at 1508 ng/g, 5-ring at 789 ng/g, and 6-ring at 369 ng/g) and 76% of degradation was required to meet the remediation goals. The removal efficiency was 5.3-72.8%, 10.7-39.1%, 0-30.9% and 31.5-68.3% by KMnO 4 , Na 2 S 2 O 8 , conventional Fenton and modified Fenton, respectively. Results demonstrated a medium reduction of a mixture of 16 PAHs in sediments; only in case of using KMnO 4 that showed the highest removal efficiency (72.8%) using a considerably large amount of oxidizer. Modified Fenton showed remarkable improvement in removal efficiency compared with the conventional Fenton method. Sodium citrate resulted in the maximum contaminant removal through H 2 O 2 activation at near neutral pH environment. Sodium pyrophosphate and sodium oxalate at higher dosages could cause negative effect on the removal efficiency. In general, the degradation of PAHs in slurry system was limited, which could be attributed to the availability and reactivity of PAHs and physical-chemical composition of the sediment.

View PDFchevron_right
Wood Filters as an Innovative Treatment Method for Roadway Runoff Pollutants
Thomas Boving

A significant amount of contamination enters water bodies from stormwater runoff. To control this runoff, detention ponds are installed at many locations to reduce the amount of pollution entering the environment. Detention ponds do not effectively remove dissolved constituents, such as heavy metals and PAHs. Previous research demonstrated that wood fibers could be utilized to enhance the removal of dissolved contaminants under laboratory conditions. A pilotscale aspen wood filter was installed at a detention pond in Providence, RI to determine if wood fibers could effectively remove contaminants from the water under field conditions. Four filters were installed to determine sorption of nitrate, phosphate, copper, iron, and PAHs as a function of differences in wood mass, different residence times, and changes in temperature and pH.

View PDFchevron_right
Evaluation of waste biomasses and their biochars for removal of polycyclic aromatic hydrocarbons
Luciane Romao

Journal of environmental management, 2017

This work evaluates the use of biomasses and their biochars as adsorbents to remove polycyclic aromatic hydrocarbons from water. Coconut waste (CW) and orange waste (OW) were pyrolyzed at 350 °C to produce the corresponding biochars (BCW and BOW). Adsorption tests using a mixed solution of benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, and dibenzo(a,h)anthracene showed removal percentages of 30.33-83.43% (CW), 47.09-83.02% (BCW), 24.20-74.25% (OW), and 23.84-84.02% (BOW). The adsorption mechanisms appeared to involve π-π interactions of similar groups of the adsorbate and adsorbent, together with hydrophobic effects. There was no indication of competition between the PAHs for the adsorption sites, and there was evidence of cooperative adsorption. The PAHs could be desorbed from the adsorbents with efficiencies in the range 34.88-72.32%, and the reuse of the adsorbents in two further cycles demonstrated their potential for use in the removal of PAHs f...

View PDFchevron_right

References (26)

  1. Barton, A.F.M., 1975. Solubility parameters. Chem. Rev. 75, 731-753.
  2. Bjoerseth, A., Ramdahl, T. (Eds.), 1985. Handbook of Poly- cyclic Aromatic Hydrocarbons, vol. 2. Marcel Dekker, New York.
  3. Boving, T.B., 2002. Chemical retention capacity of a newly constructed roadway runoff detention pond system. URI Transportation Center Research Report No. 536132, Kings- ton, RI.
  4. Brown, P.A., Gill, S.A., Allen, S.J., 2000. Metal removal from wastewater using peat. Water Res. 34, 3907-3916.
  5. Brusseau, M.L., Hu, Q., Srivastava, R., 1997. Using flow interruption to identify factors causing nonideal contami- nant transport. J. Contam. Hydrol. 24, 205-219.
  6. Bryant, P.S., Petersen, J.N., Lee, J.M., Brouns, T.M., 1992. Sorption of heavy metals by untreated red fir dust. Appl. Biochem. Biotechnol. 34/35, 774-788.
  7. Cimino, G., Passerini, A., Toscano, G., 2000. Removal of toxic cations and Cr(VI) from aqueous solution by hazelnut shell. Water Res. 34 (11), 2955-2962.
  8. Conrad, J., Burch, E.R., 1995. Highway runoff manual. M 31-16, Environmental and Engineering Service Center, February 1995.
  9. Edwards, N.T., 1983. Polycyclic aromatic hydrocarbons (PAHs) in the terrestrial environment--A review. J. Envi- ron. Qual. 12, 427-441.
  10. Fengel, D., Wegner, G., 1989. Wood: Chemistry Ultrastructure Reactions. Walter de Gruyter, Berlin.
  11. Fetter, C.W., 1998. Contaminant Hydrogeology, second ed. Prentice Hall.
  12. FHWA, 1999. Is Highway runoff a serious problem? US Department of Transportation, Federal Highway Adminis- tration, Research, Development, and Technology, Turner- Fairbank Highway Research Center, McLean, VA.
  13. Garbarini, D.R., Lion, L.W., 1986. Influence of the nature of soil organics on the sorption of toluene and trichloroethyl- ene. Environ. Sci. Technol. 20, 1263-1269.
  14. Harvey, R.G., 1991. Polycyclic Aromatic Hydrocarbons: Chemistry and Carcinogenicity. Cambridge University Press, Cambridge, England.
  15. Hoffman, C.D., Mills, G.L., Latimer, J.S., Quinn, J.G., 1984. Urban runoff as a source of polycyclic aromatic hydrocar- bons to coastal waters. Environ. Sci. Technol. 18, 580- 587.
  16. LfUBW, 1995. Hydraulische und pneumatische in-situ ver- fahren--materialien zur altlastenbearbeitung. Band 16. Landesanstalt f€ u ur Umweltschutz Baden-W€ u urttemberg, 76185 Karlsruhe, Germany.
  17. Mackay, A.A., Gschwend, P.M., 2000. Sorption of monoaro- matic hydrocarbons to wood. Environ. Sci. Technol. 34, 839-845.
  18. Mackay, A.A., Gschwend, P.M., 2001. Enhanced concentration of PAHs in groundwater at a coal tar site. Environ. Sci. Technol. 35, 1320-1328.
  19. Ricordel, S., Taha, S., Cisse, I., Dorange, G., 2002. Heavy metals removal by adsorption onto peanut husks carbon: characterization, kinetic study and modeling. Sep. Purif. Technol. 24, 389-401.
  20. Schneegurt, M.A., Jain, J.C., Menicucci, J.A., Brown, S.A., Kemner, K.M., Garofalo, D.F., Quallick, M.R., Neal, C.R., Kulpa, C.F., 2001. Biomass byproducts for the remediation of wastewaters contaminated with toxic metals. Environ. Sci. Technol. 35, 3786-3791.
  21. Schwarzenbach, R.P., Gschwend, P.M., Imboden, D.M., 1993. Environmental Organic Chemistry. Wiley Interscience, New York.
  22. Trapp, S., Miglioranza, K., Mosbaek, H., 2001. Sorption of lipophilic organic compounds to wood and implications for their environmental fate. Environ. Sci. Technol. 35, 1561- 1566.
  23. US Department of Transportation, 1994. Transportation sta- tistics: annual report 1994. Bureau of Transportation Statistics, US Dept. Transportation.
  24. US Department of Transportation, 1999. Transportation sta- tistics: annual report 1999. Bureau of Transportation Statistics. US Dept. Transportation.
  25. US Environmental Protection Agency, 1999. Preliminary data summary of urban storm water best management practices. United States Office of Water (4303) EPA-821-R-99-012. Environmental Protection Agency, Washington, DC 20460, USA. Van Metre, P., Mahler, B.J., Furlong, E.T., 2000. Urban sprawl leaves its PAH signature. Environ. Sci. Technol. 34, 4064- 4070.
  26. Wornat, M.J., Ledesma, E.B., Sandrowitz, A.K., Roth, M.J., Dawsey, S.M., Qiao, Y., Chen, W., 2001. Polycyclic aromatic hydrocarbons identified in soot extracts from domestic coal-burning stoves of Henan province, China. Environ. Sci. Technol. 35, 1943-1952.

Related papers

2003 The sorption characteristics of PAHs onto soils in the presence of synthesitic and biosrfactqans (Chang).pdf
Chin-pao Huang

Contaminants such as polycyclic aromatic hydrocarbons (PAHs) are of special concern due to their high toxicities and hydrophobicities. The high hydrophobic natures of PAHs enable their strong sorption onto soil or sediments, which makes it difficult for their removal from the environment. This study was to explore the sorption characteristics of PAHs with synthetic nonionic surfactant and biosurfactant in the soil. Two surfactants (one synthetic and one naturally occurring) Triton X-100 and rhamnolipid were used. Results show that the partition coefficient of PAHs in the Triton X-100 system decreases with increasing surfactant concentrations. Throughout the whole concentration range of studied biosurfactant (0 ~ 30 CMC), the partition coefficient of PAHs in rhamnolipid system is roughly constant, around 400.0 L/Kg.

View PDFchevron_right
Removal of Polycyclic Aromatic Hydrocarbons from Polluted Water Using Constructed Wetlands: A Review
Alexandros Gazis, Georgios Gikas, Erietta Chamalidou

Skeena Publishers, International Journal on Engineering Technologies and Informatics, 2022

During the last decades, Polycyclic Aromatic Hydrocarbons (PAHs) are detected in agricultural soils and water bodies at concentrations higher than permitted limits. The main sources of PAHs are fossil fuels, biomass burning, waste incineration, and pesticides. They harm aquatic ecosystems and organisms and pose a high risk to human health. For these reasons, several laws have been enacted to regulate the permitted concentration levels of PAHs in the environment and specifically, the wastewater discharged into aquatic ecosystems. Several methods for the removal of PAHs from wastewater exist which, although efficient, are not used extensively due to their high installation and operation cost. Constructed Wetlands (CWs) constitute an effective, practical, and low-cost option for PAHs removal from polluted waters. This paper focuses on the various treatment processes for the removal of PAHs. Research findings indicated that vertical flow CWs and hybrid systems are more effective in removing PAHs.

View PDFchevron_right
REMEDIATION Sorption of Low Molecular Mass Polycyclic Aromatic Hydrocarbons to Organic Carbon Deficient Aquifer Materials Coated with Residual Diesel Oil
RONDALL J. HUDSON, Irena Atanassova

Sorption of low molecular mass (LMM) polycyclic aromatic hydrocarbons (PAHs) acenapthene, fluorene, and dibenzo-thiophene, as tracers in columns containing aquifer materials with a mass fraction of natural organic carbon foe= 0.0002 and coated with 0 to 0.02 % of mass of a moderately weathered diesel oil was studied. Weathered diesel oil effectively retarded the transport of PAHs through aquifer materials. Sorption coefficients (K) for P AHs increased from 2 to I 0 times linearly with diesel oil content. By comparing sorption coefficients (Koii) to carbon-normalized sorption coefficients (Koc), we established that weathered diesel oil was Journal of Balkan Ecology, vol. 19, No 1, 2016 more effective as a sorptive phase than natural organic matter per unit mass. The oc-tanol-water coefficients (Kow) were found to be reasonable estimates of Koil values. Contaminants removal remediation strategies for diesel oil contaminated aquifer systems may require larger volumes of water and longer pumping times if sorptive effects of diesel oil are not considered.

View PDFchevron_right
Kinetics and Potential Significance of Polycyclic Aromatic Hydrocarbon Desorption from Creosote-Treated Wood
Bondi Gevao

Environmental Science & Technology, 1998

PAHs are major constituents of creosote, and it has been suggested that their volatilization from treated wood could make a major contribution to the U.K. atmospheric emission inventories. This paper reports a study to elucidate the volatilization characteristics of selected PAHs from creosotetreated wood and to estimate the potential significance of this source to the U.K. atmospheric source inventory. Desorption kinetics from untreated and treated wood were measured at 4 and 30°C for five PAHs (acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene) using chambers in the laboratory. Rates of desorption followed first-order kinetics for all compounds and were higher at 30 than 4°C. Mean ∑PAH fluxes varied from 2.57 ( 1.52 to 29.5 ( 6.1 mg/m 2 treated wood/day at 4 and 30°C, respectively. A prolonged study of the kinetics at 4°C showed that the volatilization rate remained constant over about 7 weeks, after which >85% of the compounds still remained sorbed on the wood. Initial desorption rates were governed by partitioning between the substrate (wood) and air and subsequently by the rates of compound diffusion from the interstices of the wood. A strong negative correlation was observed when the percent increment in the desorption rate from 4 to 30°C was plotted as a function of the octanol-air partition coefficient (K OA ) (r 2 ) -0.93); vapor pressure was strongly positively correlated (r 2 ) 0.92). Desorption half-lives ranged from 0.7 to 31 yr at 4°C and from 0.3 to 1 yr at 30°C for fluoranthene and acenaphthene, respectively. Estimates of annual U.K. emissions for the compounds specified from freshly treated wood (i.e., ignoring long-term releases from previously treated wood) were subject to a number of important assumptions, but were in the range of ∼100 t ∑PAH. This is less than the annual U.K. emissions of ∑PAHs estimated for domestic heating (∼600 t) and believed to be similar to that from vehicle emissions (∼80 t) at the present time.

View PDFchevron_right
Advances in water treatment technologies for removal of polycyclic aromatic hydrocarbons: Existing concepts, emerging trends, and future prospects
ADEOLA Adedapo Oluwasanu

Water Environment Research, 2020

In the last two decades, environmental experts have focused on the development of several biological, chemical, physical, and thermal methods/technologies for reme-diation of PAH-polluted water. Some of the findings have been applied to field-scale treatment, while others have remained as prototypes and semi-pilot studies. Existing treatment options include extraction, chemical oxidation, bioremediation, photocatalytic degradation, and adsorption (employing adsorbents such as biomass derivatives, geosorbents, zeolites, mesoporous silica, polymers, nanocomposites, and graphene-based materials). Electrokinetic remediation, advanced phytoremediation, green nanoremediation, enhanced remediation using biocatalysts, and integrated approaches are still at the developmental stage and hold great potential. Water is an essential component of the ecosystem and highly susceptible to PAH contamination due to crude oil exploration and spillage, and improper municipal and industrial waste management, yet comprehensive reviews on PAH remediation are only available for contaminated soils, despite the several treatment methods developed for the remediation of PAH-polluted water. This review seeks to provide a comprehensive overview of existing and emerging methods/technologies, in order to bridge information gaps toward ensuring a green and sustainable remedial approach for PAH-contaminated aqueous systems. © 2020 Water Environment Federation • Practitioner points • Comprehensive review of existing and emerging technologies for remediation of PAH-polluted water. • Factors influencing efficiency of various methods, challenges and merits were discussed. • Green nano-adsorbents, nano-oxidants and bio/phytoremediation are desirous for ecofriendly and economical PAH remediation. • Adoption of an integrated approach for the efficient and sustainable remediation of PAH-contaminated water is recommended.

View PDFchevron_right

Related topics

  • Polycyclic aromatic hydrocarbons...
  • Material Balance
  • Adsorption Isotherm Models

    • Cited by

    Modified kraft lignin for bioremediation applications
    Diva Santos

    Journal of Environmental Science and Health Part A-toxic/hazardous Substances & Environmental Engineering, 2012

    This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

    View PDFchevron_right
    Kinetic and Removal Mechanisms of Ethylbenzene from Contaminated Solutions by Chitin and Chitosan
    Sabeha Ouki

    Water, Air, & Soil Pollution, 2011

    In this study, the efficiency of chitin and chitosan toward the removal of ethylbenzene from aqueous solutions was investigated. Batch adsorption experiments of ethylbenzene-contaminated waters (5-200 mg/L) were carried out to evaluate the removal performance. Ethylbenzene uptake was determined from the changes in concentration, as the residual concentration was measured by gas chromatography with mass spectroscopy. The results indicated that the adsorption of ethylbenzene by chitin and chitosan were in agreement with the Langmuir isotherm, for two parameters model, and Redlich-Peterson isotherm, for three parameters model. A maximum removal percentage of 65% of ethylbenzene can be achieved using chitosan as adsorbent material. The adsorption capacity of ethylbenzene followed the order chitosan>chitin. The pseudo-second order rate model described best the adsorption kinetics of ethylbenzene for the two selected adsorbents. The kinetic studies also revealed that the pore diffusion is not the only rate controlling step in the removal of ethylbenzene. Overall, the study demonstrated that chitosan is a potential adsorbent for the removal of ethylbenzene at concentrations as high as 200 mg/L.

    View PDFchevron_right
    Remediation of Contaminated Waters with Microplastics
    irma silva

    Handbook of Microplastics in the Environment, 2020

    Polymeric materials have had an exponential growth since the Second World War, so that in 2018 the annual world production was 359 million tons. This has generated a contamination problem because of its prolonged exposure to various chemical and environmental factors which have caused the formation of particles with a size less than 5 mm with a vast surface area and chemically stable and adjustable surface. For these reasons, these particles called microplastics (MPs) have been used as vectors for chemicals in the environment and, recently, in the removal of several pollutants from water. In this chapter, some representative examples of the use of microplastics for sorption of contaminants from water (pharmaceuticals, metal ions, and other organic compounds) are shown. The chapter is organized into two parts: the first part addresses MPs of commercial origin (virgin) and those reused after being

    View PDFchevron_right
    A critical review of contaminant removal by conventional and emerging media for urban stormwater treatment in the United States
    Fanny Okaikue-Woodi

    Water Research, 2020

    Stormwater is a major component of the urban water cycle contributing to street flooding and high runoff volumes in urban areas, and elevated contaminant concentrations in receiving waters from contact with impervious surfaces. Engineers and city planners are investing in best management practices to reduce runoff volume and to potentially capture and use urban stormwater. However, these current approaches result in moderate to low contaminant removal efficiencies for certain classes of contaminants (e.g., particles, nutrients, and some metals). This review describes options and opportunities to augment existing stormwater infrastructure with conventional and emerging reactive media to improve contaminant removal. This critical analysis characterizes media physicochemical properties and mechanisms contributing to contaminant removal, describes possible candidates for new engineered media, highlights lab and field studies investigating stormwater media contaminant removal, and identifies possible limitations and knowledge gaps in media implementation. Following this analysis, information is provided regarding factors that may contribute to or adversely impact urban stormwater treatment by media. The review closes with insights into additional research directions and important information necessary for safe and effective urban stormwater treatment using media.

    View PDFchevron_right
    580 California St., Suite 400
    San Francisco, CA, 94104
    © 2025 Academia. All rights reserved