Remediation of an aged PCP-contaminated soil by chemical oxidation under flow-through conditions

Abstract

To cite this version:V. Rybnikova, N. Singhal, K Hanna. Remediation of an aged PCP-contaminated soil by chemical oxidation under flow-through conditions. Chemical Engineering Journal, Elsevier, 2017Elsevier, , 314, pp.202-211. 10.1016Elsevier, /j.cej.2016 AbstractIn this study the oxidation of pentachlorophenol (PCP) in an aged contaminated soil was performed under both water-unsaturated and water-saturated conditions using potassium permanganate (PM), potassium persulfate (PS) and hydrogen peroxide (HP). Overall, the results of PCP removal extent and oxidant decomposition indicated that the water content in column has no significant impact on the oxidation performance. The increase in flow rate from 0.025 to 2.5 mL min -1 decreased the oxidant decomposition as well as the PCP degradation extent, except for HP that is highly reactive.Kinetic limitations in column may explain the effect of residence time of oxidant on the degradation performance. Consistently, re-circulation of oxidant solutions in a closed loop system improved the oxidation efficiency and oxidant decomposition extents in case of PS and PM, but not for HP .Surprisingly, attempts to enhance the PCP availability in soil by using solubility agents or by heating did not improve the degradation efficiency in soil. The presence of methyl-β-cyclodextrin Key words: pentachlorophenol; contaminated soil; oxidation; column; mobilization. 3 IntroductionPentachlorophenol ( Soil preparation and characterizationContaminated soil used in this study was obtained from a timber mill in Waipa district of Waikato Region, New Zealand. Prior to experiments, soil was dried, ground and passed through 1 mm (18 mesh) sieve. Obtained fraction was characterized by the Institute en Santé Agro Environnement (ISAE), Combourg, France. Soil characteristics are presented in Table 1. According to particle size distribution, the soil is classified as loamy sand. The soil is slightly carbonated and has a pH of 7.2.It contains 1.5% of organic matter and high concentrations of iron (9.8 g kg -1 ) and exchangeable cations (1.5 g kg -1 ). The total PCP concentration in soil is 6 mg kg -1 , which is above the quality 6 criteria of soil for agricultural use in New Zealand and considered as a soil with serious risk in NewZealand as well as in Europe [22].Iron speciation in soil. Iron speciation was performed using methods described by Van Bodegom et al. [23]. Total Fe content was determined by the extraction of 2 g of soil with 10 N HCl.Amorphous iron was extracted with oxalate solution (0.113 M sodium oxalate/0.086M oxalic acid). Experimental set-upFor preliminary tests, 2 g of PCP contaminated soil was transferred into glass vial of 40 ml and then mixed with oxidant solution. Final volume of reaction suspension was maintained at 2 ml to provide liquid/solid (L/S) ratio of 1:1. In experiments with magnetite or Fe 0 , nanoparticles were added and homogenized with the soil by magnetic stirring (400 rpm) before adding the oxidant. Blank tests were carried out without oxidants (with 2 ...

Enhancement of Pentachlorophenol Removal in a Historically Contaminated Soil by Adding Ascorbic Acid to H2O2/Magnetite System

“…For this, reagent solutions are injected from the bottom of the column in an upward direction. Choosing saturated conditions eliminate any preferential pathways by uniform distribution of the reagents in the soil column for better treatment [19]. Briefly, glass columns were packed with 5 g of PCP-contaminated soil pre-mixed with magnetite (5 g kg −1 soil w/w).…”

“…The PCP was extracted from soil slurries, as reported elsewhere [19]. For this, in an ultrasonic bath, water/methanol solution (50/50, v/v) was blended with soil slurries (L/S ratio: 2/1) for 1 h. This was followed by 10 min of centrifugation at 4000 rpm.…”

“…Based on our knowledge, this study is the first report of soil application of AA-mediated magnetite Fenton oxidation. PCP has been used as a wood preservative and pesticide for more than 100 years and its extensive use has resulted in its ubiquitous contamination in water and soil [19]. It is listed among the persistent organic pollutants under the Stockholm Convention.…”

Ferrate(VI) oxidation of pentachlorophenol in water and soil

“…PCP appears to be an ideal candidate due to its classification among persistent organic pollutants (Stockholm Convention), and its widespread contamination in soil and water (Rybnikova et al, 2017). PCP can be efficiently degraded in aqueous solution through biological, physical and chemical treatments (Chen et al, 2018;Guemiza et al, 2017;Rybnikova et al, 2017;Xue et al, 2017;Zimbron and Reardon, 2009). To our knowledge, there exists only two studies which focused on the use of ferrate(VI) to remove PCP in water (Homolkova et al, 2016(Homolkova et al, , 2017 The soil was dried, ground and sieved through 1 mm mesh.…”

Application and Selection of Remediation Technology for OCPs-Contaminated Sites by Decision-Making Methods

“…There are many kinds of remediation technologies for POPs-contaminated sites, including gas phase extraction [25,26,27,28,29], soil leaching [30,31,32,33], vitrification [34,35], chemical oxidation [36,37,38,39], incineration method [40,41,42,43], cement kiln co-disposal method [44,45,46,47], thermal desorption [48,49,50], and bioremediation [51,52,53]. The principle is either to increase the usability of contaminated soil through physical and chemical methods, or to degrade the contaminating chemicals through chemical or biological methods.…”