Effect of soil pH and organic matter on the adsorption and desorption of pentachlorophenol

Abstract

Various properties of soil affect the partition of organic contaminants within, and conversely, the properties of the organic contaminants also directly affect their partition behavior in soil. Therefore, understanding the effects of various properties of soil on the partition of organic contaminants favors subsequent assessment and provides soil remediation methods for policymakers. This study selected pentachlorophenol (PCP), a common hydrophobic ionizable organic compound in contaminated sites worldwide, as the target contaminant. The effects of pH, organic matter, and the combination of both, on PCP adsorption/desorption behavior in soil were investigated. Phosphoric acid and potassium hydroxide were used as buffer solutions to modify the soil pH by the batch and column extraction methods. A common retail organic fertilizer and fulvic acid were selected as additives to manipulate the soil organic content. Modifying the pH of the soil samples revealed that acidic soil exhibited a greater PCP adsorption rate than alkaline soil. The amount of PCP desorption increased regardless of pH of the in situ contaminated soil. The adsorption of PCP increased with increasing amount of organic additive. However, addition of fulvic acid yielded different results compared to the addition of organic fertilizer. Specifically, the organic fertilizer could not compete with the in situ contaminated soil in PCP adsorption, whereas fulvic acids increased the PCP dissolution to facilitate adsorbing contaminant adsorption. The combined effect of pH modification and organic matter addition provides additional PCP adsorption sites; therefore, adding the organic fertilizer to decrease the soil pH elevated the PCP adsorption rates of the laterite, alluvial, and in situ contaminated soil samples. The study results revealed that both pH and organic matter content are crucial to PCP adsorption/desorption in soil. Therefore, the effects of soil pH and organic matter should be considered in facilitating PCP treatment for soil remediation.

Assessing the performance of different irrigation systems on lettuce (Lactuca sativa L.) in the greenhouse

“…This may be because soil temperature and humidity increased and promoted the release of N nutrients during the early stages under the plastic film mulching treatments. The alkali-hydrolyzable N content may have subsequently improved and a large concentration of nitric nitrogen led to the decrease of soil pH [34, 35]. The results presented in S3 Table indicate that plastic film mulching treatment had a lower EC than non-plastic film mulching.…”

Profiling of Indigenous Biosurfactant-Producing Bacillus Isolates in the Bioremediation of Soil Contaminated by Petroleum Products and Olive Oil

“…Several studies have shown that a correlation between pH and microorganisms in bioremediation efficacy. e pentachlorophenol molecules can be biodegraded with the variation of pH and organic matter [28]. ese were confirmed by the soil electrical conductivity measures [29].…”

Physical and chemical soil quality and litter stock in agroforestry systems in the Eastern Amazon

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