Search query: Removal of hydrocarbons from water technologies

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abstract: Hydrocarbons contamination of the marine environment generated by the offshore oil and gas industry is generated from a number of sources including oil contaminated drill cuttings and produced waters. The removal of hydrocarbons from both these sources is one of the most significant challenges facing this sector as it moves towards zero emissions. The application of a number of techniques which have been used to successfully destroy hydrocarbons in produced water and waste water effluents has previously been reported. This paper reports the application of semiconductor photocatalysis as a final polishing step for the removal of hydrocarbons from two waste effluent sources. Two reactor concepts were considered: a simple flat plate immobilised film unit, and a new rotating drum photocatalytic reactor. Both units proved to be effective in removing residual hydrocarbons from the effluent with the drum reactor reducing the hydrocarbon content by 90% under 10 minutes.
author_names: Morgan Adams

Ian Campbell

Peter K J Robertson
title: Novel photocatalytic reactor development for removal of hydrocarbons from water
year: 2008

abstract: Arsenic's history in science, medicine and technology has been overshadowed by its notoriety as a poison in homicides. Arsenic is viewed as being synonymous with toxicity. Dangerous arsenic concentrations in natural waters is now a worldwide problem and often referred to as a 20th 21st century calamity. High arsenic concentrations have been reported recently from the USA, China, Chile, Bangladesh, Taiwan, Mexico, Argentina, Poland, Canada, Hungary, Japan and India. Among 21 countries in different parts of the world affected by groundwater arsenic contamination, the largest population at risk is in Bangladesh followed by West Bengal in India. Existing overviews of arsenic removal include technologies that have traditionally been used (oxidation, precipitation/coagulation/membrane separation) with far less attention paid to adsorption. No previous review is available where readers can get an overview of the sorption capacities of both available and developed sorbents used for arsenic remediation together with the traditional remediation methods. We have incorporated most of the valuable available literature on arsenic remediation by adsorption approximately 600 references) Existing purification methods for drinking water; wastewater; industrial effluents, and technological solutions for arsenic have been listed. Arsenic sorption by commercially available carbons and other low cost adsorbents are surveyed and critically reviewed and their sorption efficiencies are compared. Arsenic adsorption behavior in presence of other impurities has been discussed. Some commercially available adsorbents are also surveyed. An extensive table summarizes the sorption capacities of various adsorbents. Some low cost adsorbents are superior including treated slags, carbons developed from agricultural waste (char carbons and coconut husk carbons) biosorbents (immobilized biomass, orange juice residue) goethite and some commercial adsorbents, which include resins, gels, silica, treated silica tested for arsenic removal come out to be superior. Immobilized biomass adsorbents offered outstanding performances. Desorption of arsenic followed by regeneration of sorbents has been discussed. Strong acids and bases seem to be the best desorbing agents to produce arsenic concentrates. Arsenic concentrate treatment and disposal obtained is briefly addressed. This issue is very important but much less discussed.
author_names: Dinesh Mohan

Charles U Pittman
title: Arsenic removal from water/wastewater using adsorbents A critical review.
venue: Journal of hazardous materials
year: 2007

abstract: A screening method was developed to evaluate the oil removal capability of biosurfactants for oil contaminated soils collected from a heavy oil polluted site. The ability of removing total petroleum hydrocarbon (TPH) from soil by two biosurfactants was identified and compared with that of synthetic surfactants. The results show that biosurfactants exhibited much higher TPH removal efficiency than the synthetic ones examined. By using 0.2 mass% of rhamnolipids, surfactin, Tween 80, and Triton X 100, the TPH removal for the soil contaminated with ca. 3,000 mg TPH/kg dry soil was 23% 14% 6% and 4% respectively, while removal efficiency increased to 63% 62% 40% and 35% respectively, for the soil contaminated with ca. 9000 mg TPH/kg dry soil. The TPH removal efficiency also increased with an increase in biosurfactant concentration (from 0 to 0.2 mass% but it did not vary significantly for the contact time of 1 and 7 days.
author_names: Chin Chi Lai

Yi-Chien Huang

Yu-Hong Wei

Jo-Shu Chang
title: Biosurfactant enhanced removal of total petroleum hydrocarbons from contaminated soil.
venue: Journal of hazardous materials
year: 2009

abstract: In the present study electrocoagulation (EC) has been evaluated as a treatment technology for arsenite [As(III) and arsenate [As(V) removal from water. Laboratory scale experiments were conducted with three electrode materials namely, iron, aluminum and titanium to assess their efficiency. Arsenic removal obtained was highest with iron electrodes. EC was able to bring down aqueous phase arsenic concentration to less than 10 microgl( 1) with iron electrodes. Current density was varied from 0.65 to 1.53 mAcm( 2) and it was observed that higher current density achieved rapid arsenic removal. Experimental results at different current densities indicated that arsenic removal was normalized with respect to total charge passed and therefore charge density has been used to compare the results. Effect of pH on arsenic removal was not significant in the pH range 6 8. Comparative evaluation of As(III) and As(V) removal by chemical coagulation (with ferric chloride) and electrocoagulation has been done. The comparison revealed that EC has better removal efficiency for As(III) whereas As(V) removal by both processes was nearly same. The removal mechanism of As(III) by EC seems to be oxidation of As(III) to As(V) and subsequent removal by adsorption/complexation with metal hydroxides generated in the process.
author_names: P Ratna Kumar

Sanjeev Chaudhari

Kartic C Khilar

S P Mahajan
title: Removal of arsenic from water by electrocoagulation.
venue: Chemosphere
year: 2004

abstract: Nitrate contamination in groundwater resources originates mainly from the excessive use of fertilisers and uncontrolled land discharges of treated wastewater. This can cause potential health hazards to infants and pregnant women, thus limiting the direct use of the groundwater resources for the human consumption in several parts of the world, including India. The conventional processes used to eliminate nitrate from water are ion exchange, reverse osmosis and electro dialysis. The utility of these processes has been limited due to their expensive operation and subsequent disposal problem of the generated nitrate waste brine. This paper presents a comprehensive account of the methods/techniques used for the removal of nitrate ion from water during the last 10 years with special reference to the biological denitrification and fate of the metals in decontamination processes.
author_names: Madhusudan Shrimali

K P Singh
title: New methods of nitrate removal from water.
venue: Environmental pollution
year: 2001

abstract: Phytoremediation is an emerging technology that uses plants to clean up pollutants (metals and organics) from the environment. Within this field of phytoremediation, the utilization of plants to transport and concentrate metals from the soil into the harvestable parts of roots and above ground shoots is usually called phytoextraction. Most traditional remediation methods do not provide acceptable solutions for the removal of metals from soils. By contrast, phytoextraction of metals is a cost effective approach that uses metal accumulating plants to clean up these soils. Subsequently, the harvestable parts, rich in accumulated metals, can be easily and safely processed by drying, ashing or composting. Some extracted metals can also be reclaimed from the ash, generating recycling revenues. Phytoextraction appears a very promising technology for the removal of metal pollutants from the environment and may be, at present, approaching commercialization.
author_names: Carlos Garbisu

Itziar Alkorta
title: Phytoextraction: a cost effective plant based technology for the removal of metals from the environment.
venue: Bioresource technology
year: 2001

abstract: Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM) and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.
author_names: Venkata K K Upadhyayula

S Deng

Martha C Mitchell

Geoffrey B Smith
title: Application of carbon nanotube technology for removal of contaminants in drinking water: a review.
venue: The Science of the total environment
year: 2009

abstract: The available technologies for the abatement of phenol from water and gaseous streams are briefly reviewed, and the recent advancements summarized. Separation technologies such as distillation, liquid liquid extraction with different solvents, adsorption over activated carbons and polymeric and inorganic adsorbents, membrane pervaporation and membrane solvent extraction, have been discussed. Destruction technologies such as non catalytic, supercritical and catalytic wet air oxidation, ozonation, non catalytic, catalytic and enzymatic peroxide wet oxidation, electrochemical and photocatalytic oxidation, supercritical wet gasification, destruction with electron discharges as well as biochemical treatments have been considered. As for the abatement of phenol from gases, condensation, absorption in liquids, adsorption on solids, membrane separation, thermal, catalytic, photocatalytic and biological oxidation have also been considered. The experimental conditions and the performances of the different techniques have been compared.
author_names: Guido Busca

Silvia Berardinelli

Carlo Resini

Laura Arrighi
title: Technologies for the removal of phenol from fluid streams: a short review of recent developments.
venue: Journal of hazardous materials
year: 2008

abstract: Among various water purification and recycling technologies, adsorption is a fast, inexpensive and universal method. The development of low cost adsorbents has led to the rapid growth of research interests in this field. The present protocol describes salient features of adsorption and details experimental methodologies for the development and characterization of low cost adsorbents, water treatment and recycling using adsorption technology including batch processes and column operations. The protocol describes the development of inexpensive adsorbents from waste materials, which takes only 1 2 days, and an adsorption process taking 15 120 min for the removal of pollutants. The applications of batch and column processes are discussed, along with suggestions to make this technology more popular and applicable.
author_names: Imran Ali

V K Gupta
title: Advances in water treatment by adsorption technology
venue: Nature Protocols
year: 2007

abstract: Nitrate, due to its high water solubility, is possibly the most widespread groundwater contaminant in the world, imposing a serious threat to human health and contributing to eutrophication. Among several treatment technologies applied for nitrate removal, adsorption has been explored widely and offers satisfactory results especially with mineral based and/or surface modified adsorbents. In this review, an extensive list of various sorbents from the literature has been compiled and their adsorption capacities for nitrate removal as available in the literature are presented along with highlighting and discussing the key advancement on the preparation of novel adsorbents tested for nitrate removal.
author_names: Amit Bhatnagar

Mika Sillanpaa
title: A review of emerging adsorbents for nitrate removal from water
year: 2011