Influence of organic amendments on the sorption of pentachlorophenol on soils

Abstract

The influence of pH on the sorption of pentachlorophenol (PCP) onto three organic amendments, char, humic acid (HA) and peat, and the effect of organic amendments on PCP sorption to three kinds of soils were evaluated. The sorption of PCP on these sorbents fitted the Freundlich model well, suggesting that PCP sorption isotherms were nonlinear with exponential coefficient (N) value lower than 1. The PCP sorption capacity on three organic amendments and the N values increased with decreasing pH. The sorption capacities were in the order: char > HA > peat. Organic amendments resulted in an enhancement of sorption capacities of soils. The N values of PCP sorption on soils were decreased by char amendment and increased by HA and peat amendments. This study demonstrated that application of traditional organic amendments led to the enhancement of PCP sorption by soils. This information may aid both in predicting environmental fates of hydrophobic ionizable organic compounds and in developing remediation strategies for them.

Impacts of Biochar (Black Carbon) Additions on the Sorption and Efficacy of Herbicides

“…Furhermore, the lack of information within these studies to properly characterize the biochar material used further limits the ability to compare results. However, based on the analogous observations with non-biochar materials (Table 1), the overall conclusions are that biochar additions (Table 2) (Table 2); Li et al, 2009;Qiu et al, 2009b;Wang et al, 2009, ( Herbicides are much more than just weed killers. They may exhibit beneficial or adverse effects on other organisms.…”

“…The highest sorption of pentachlorophenol in all the soils was observed when the soils were amended with char, followed by humic acids, and peat. Sorption was a function of organic carbon content (Li et al, 2009). The authors reported a 2.5-20 fold increase in the K f values following the char addition.…”

“…In the case of wheat char and atrazine, one of the herbicides most used worldwide, the K f value sorption on the amendment was 2012 (Loganathan et al, 2009), and the K f increased by a factor of 5 in a sandy loam soil and of 4.3 in a clay loam soil, when both soils were amended with 1% (w/w) of wheat char. Sorption of pentachlorophenol, an organochlorine compound used as herbicide, insecticide, fungicide, algaecide, and disinfectant, was studied on three soils with different amendments (char, humic acids and peat), by Li et al (2009). The highest sorption of pentachlorophenol in all the soils was observed when the soils were amended with char, followed by humic acids, and peat.…”

“…sorption with atrazine was also studied, and a slight decrease in diuron sorption in presence of atrazine in the soil and in the amendment was also observed. The effect of the pH on pesticide sorption on the organic amendments was also studied by Li et al (2009) with the result of an increase of sorption with the decrease in pH, which changes the pentachlorophenol species, and increases the static repulsion between the sorbent surface and the anionic form of the pesticide. However, it has been suggested that the presence of oxygenated groups on char could mask the impact of pH on the sorption of herbicides (Tessmer et al, 1997).…”

Microscale scavenging of pentachlorophenol in water using amine and tripolyphosphate-grafted SBA-15 silica: Batch and modeling studies

“…1a) which has no active functional groups to interact with the predominantly negatively charged PCP (pentachlorophenolate) species in solution (Fig. 5e right) which is its ionization state at the solution pH (6.5 ± 0.2) (Li et al, 2009). Thus, the two mechanisms thought to be responsible for the removal of PCP by SBA-15 are via very weak interactions with SBA-15 external wall surfaces, which accounts for very little PCP removal, and the filling of SBA-15 mesopores by charged PCP species in solution which was significant for SBA-15.…”