Novel Photocatalytic Reactor Development for Removal of Hydrocarbons from Water

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.

Titanium compounds and their impact on the transformation of air pollutants

“…The global average in soil has been estimated as 0.33% of titanium, although it is lower for podzols and histosols. Titanium has very low mobility under almost all environmental conditions (most conditions below a pH of 2) (Adams et al 2008).…”

“…Titanium removal from water features flocculation of colloidal material, adsorption and scavenging by precipitation of Mn and Fe oxides. Consequently, Ti concentrations in natural water are generally as low as 1-3 μg l −1 (Adams et al 2008).…”

“…It may occur as a TiO 2 suspension, or as a wall coating consisted of TiO 2 film. Otherwise it could be a fixed bed, composed of TiO 2 glass rings (Adams et al 2008). Currently, the only design of a photo-reactor which is capable of processing the level of wastewater required is that of suspension reactors.…”

“…Moreover, the application of semiconductors in photocatalysis for remediation has real scope for impacting water pollution and, hence, global water scarcity (McCullagh et al 2011). Adams et al (2008) have reported the comparison of a standard flat plate reactor with a novel drum reactor (Robertson et al 2004) for the removal of organic (oil and gas hydrocarbons) contaminants from the water. The drum reactor concept was a single pass continuous flow system.…”

“…Such a high level of reduction over a short period of time is attributed to samples passing through 3 consecutive drums, each with 200 g of TiO 2 catalyst present. Therefore, 600 g of catalyst are utilized for the entire system (Adams et al 2008, McCullagh et al 2011. It is important to understand that there is no sense in applying these kinds of catalysts in doses exceeding those confirmed effective by research.…”