Remediation of a biodiesel blend-contaminated soil by using a modified Fenton process

Abstract

A soil contaminated with a B20 biodiesel blend (20 % biodiesel, 80 % diesel) has been treated by modified Fenton process with or without chelant addition. All experiments were conducted without pH adjustment. The reagents used were as follows: hydrogen peroxide as oxidant (400-4,000 mmol L(-1)), ferric ion as catalyst (5-20 mmol L(-1)), and trisodium citrate (50 mmol L(-1)) as chelating agent. Soil was spiked at two different pollutant concentrations (1,000-10,000 mg diesel kg(-1) soil). Higher total petroleum hydrocarbon (TPH) removal efficiencies were obtained (up to 75 %) after the treatment in the absence of the chelant due to the low pH obtained in this case. In the presence of chelant, the TPH conversion obtained was lower because both higher pH is obtained and chelant competes with diesel for the oxidant. On the other hand, at neutral pH, the lifetime of the oxidant was increased. Fatty acid methyl esters (FAMEs) are easier to remove than diesel aliphatic hydrocarbons from the blend. An important decrease of the aqueous phase toxicity was observed after the modified Fenton reaction, supporting that nontoxic by-products were released to the aqueous phase during the treatment.

Fate of iron and polycyclic aromatic hydrocarbons during the remediation of a contaminated soil using iron-activated persulfate: A column study

“…Soil properties and the characterization procedure, except the determination of the hydraulic conductivity, are detailed in previous works (Pardo et al, 2014;Vicente et al, 2012). Soil spiking was carried out as reported elsewhere (Kulik et al, 2006;Mora et al, 2014;Peluffo et al, 2015), spreading slowly an acetone stock solution of the contaminants to the clean soil, being mixed manually with a spatula simultaneously.…”

Remediation of soil contaminated by PAHs and TPH using alkaline activated persulfate enhanced by surfactant addition at flow conditions

“…The soil selected for this study was a sandy clay loam Bt horizon from the Autonomous Community of Madrid. Property values such as pH = 7.22, total organic carbon = 0.196% and labile iron = 7235 mg kg −1 , dp < 2 mm and hydraulic conductivity = 14.1 cm day −1 , were characterized in previous work , . The spiking procedure was developed according to the literature , , .…”

Remediation technologies for oil-contaminated sediments

“…Although Fenton's reagent\Fenton-like reactions and ozone have been most commonly used for remediation, the modified Fenton's process is more costeffective than ozonation due to the low amounts added and the chemical cost (Goi et al, 2006b). Moreover, the strong oxidizing capabilities of Fenton's process holds promise for the effective remediation of oilcontaminated sediments (Pardo et al, 2014). During Fenton's process, highly active hydroxyl radicals are generated from the reaction between hydrogen peroxide and soluble ferrous or ferric salts acting as the catalyst:…”

“…Therefore, the pH must be adjusted both before and after treatment of any contaminated site (Watts and Teel, 2005). To overcome these limitations, organic and inorganic chelating agents are often used, allowing Fenton's process to occur at a neutral pH (Lu et al, 2010;Pardo et al, 2014;Venny et al, 2012). Chelating agents prevent the precipitation of iron catalysts into iron oxyhydroxides (Fe(OH) 3 ).…”

“…Chelating agents prevent the precipitation of iron catalysts into iron oxyhydroxides (Fe(OH) 3 ). In general, chelating agents are not efficient in oxidation by hydroxyl radicals, such that the efficiency of Fenton's process is significantly lost (Pardo et al, 2014;Rastogi et al, 2009;Sillanpää et al, 2011). Waste basic oxygen furnace slag catalyses Fenton-like oxidation for effective and efficient remediation of fuel oil-contaminated sediments (Tsai and Kao, 2009).…”