Dibutyl phthalate adsorption characteristics using three common substrates in aqueous solutions

In recent years, the presence and adverse impacts of phthalic acid esters in aquatic environments have gained increasing attention. This work investigated the adsorption behavior of a typical phthalic acid ester, dibutyl phthalate (DBP), onto steel slag, gravel, and shell sand (substrates commonly used in constructed wetlands). The influence of dissolved organic matter (DOM) on DBP adsorption was investigated using humic acid as a proxy for DOM. The results demonstrated that the adsorption of DBP to three substrates reached equilibrium within 96 h, and the adsorption kinetics were well fitted by a pseudo-second-order model. The DBP adsorption isotherms were best fitted by the Langmuir adsorption model. The DBP adsorption capacity decreased in the order of steel slag>gravel>shell sand, with values of 656 mg/kg, 598 mg/kg, and 6.62 mg/kg at 25 degrees C, respectively. DBP adsorbed to the surface of all substrates in a monolayer via an endothermic process. The DBP adsorption capacities of steel slag and gravel decreased as the DOM content increased. The DBP adsorption mechanisms to steel slag and gravel mainly involved the surface coordination of DBP with -OH or -COOH groups and electrostatic interactions. The results of this work suggest that steel slag and gravel may be ideal substrates for use in constructed wetlands to treat wastewater polluted with DBP. (C) Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature 201

dibutylphthalateadsorptioncharacteristicsusingthreecommonsubstratesinaqueoussolutions

In recent years, the presence and adverse impacts of phthalic acid esters in aquatic environments have gained increasing attention. This work investigated the adsorption behavior of a typical phthalic acid ester, dibutyl phthalate (DBP), onto steel slag, gravel, and shell sand (substrates commonly used in constructed wetlands). The influence of dissolved organic matter (DOM) on DBP adsorption was investigated using humic acid as a proxy for DOM. The results demonstrated that the adsorption of DBP to three substrates reached equilibrium within 96 h, and the adsorption kinetics were well fitted by a pseudo-second-order model. The DBP adsorption isotherms were best fitted by the Langmuir adsorption model. The DBP adsorption capacity decreased in the order of steel slag>gravel>shell sand, with values of 656 mg/kg, 598 mg/kg, and 6.62 mg/kg at 25°C, respectively. DBP adsorbed to the surface of all substrates in a monolayer via an endothermic process. The DBP adsorption capacities of steel slag and gravel decreased as the DOM content increased. The DBP adsorption mechanisms to steel slag and gravel mainly involved the surface coordination of DBP with –OH or –COOH groups and electrostatic interactions. The results of this work suggest that steel slag and gravel may be ideal substrates for use in constructed wetlands to treat wastewater polluted with DBP

Dibutyl phthalate adsorption characteristics using three common substrates in aqueous solutions

In recent years,the presence and adverse impacts of phthalic acid esters m aquatic environments have gained increasing attention.This work investigated the adsorption behavior of a typical phthalic acid ester,dibutyl phthalate(DBP),onto steel slag,gravel,and shell sand(substrates commonly used in constructed wetlands).The influence of dissolved organic matter(DOM)on DBP adsorption was investigated using humic acid as a proxy for DOM.The results demonstrated that the adsorption of DBP to three substrates reached equilibrium within 96 h,and the adsorption kinetics were well fitted by a pseudo-second-order model.The DBP adsorption isotherms were best fitted by the Langmuir adsorption model.The DBP adsorption capacity decreased in the order of steel slag>gravel>sheII sand,with values of 656 mg/kg,598 mg/kg,and 6.62 mg/kg at 25°C,respectively.DBP adsorbed to the surface of all substrates in a monolayer via an endothermic process.The DBP adsorption capacities of steel slag and gravel decreased as the DOM content increased.The DBP adsorption mechanisms to steel slag and gravel mainly involved the surface coordination of DBP with-OH or-COOH groups and electrostatic interactions.The results of this work suggest that steel slag and gravel may be ideal substrates for use in constructed wetlands to treat wastewater polluted with DBP

Dibutyl phthalate adsorption characteristics using three common substrates in aqueous solutions

In recent years,the presence and adverse impacts of phthalic acid esters m aquatic environments have gained increasing attention.This work investigated the adsorption behavior of a typical phthalic acid ester,dibutyl phthalate(DBP),onto steel slag,gravel,and shell sand(substrates commonly used in constructed wetlands).The influence of dissolved organic matter(DOM)on DBP adsorption was investigated using humic acid as a proxy for DOM.The results demonstrated that the adsorption of DBP to three substrates reached equilibrium within 96 h,and the adsorption kinetics were well fitted by a pseudo-second-order model.The DBP adsorption isotherms were best fitted by the Langmuir adsorption model.The DBP adsorption capacity decreased in the order of steel slag>gravel>sheII sand,with values of 656 mg/kg,598 mg/kg,and 6.62 mg/kg at 25°C,respectively.DBP adsorbed to the surface of all substrates in a monolayer via an endothermic process.The DBP adsorption capacities of steel slag and gravel decreased as the DOM content increased.The DBP adsorption mechanisms to steel slag and gravel mainly involved the surface coordination of DBP with-OH or-COOH groups and electrostatic interactions.The results of this work suggest that steel slag and gravel may be ideal substrates for use in constructed wetlands to treat wastewater polluted with DBP

Occurrence and risk assessment of triclosan in freshwater lakes in the middle Yangtze River basin (Wuhan, Central China)

Triclosan (TCS) is an endocrine disrupting chemical which is commonly used as a disinfectant in pharmaceuticals and personal care products (PPCP's). Since early 2020, the worldwide outbreak of COVID-19 has increased the use of PPCP's, so the occurrence and impact of TCS on freshwater lakes should be considered. However, little attention has been given to the effect of TCS on freshwater lakes in China. This study is the first attempt at a risk assessment focusing on the temporal and spatial occurrence of TCS in freshwater lakes in the middle Yangtze River basin. The surface water and sediments of Donghu Lake and Liangzi Lake (Wuhan, Central China) were collected from October 2020 to August 2021. The maximum concentrations of TCS were 466 ​ng/L and 239 ​ng/L in surface water, 71 ​ng/g and 25 ​ng/g (dry weight) in sediments of Donghu Lake and Liangzi Lake, respectively. Significant temporal and spatial differences of TCS were observed within and between the lakes, with the highest concentrations measured in winter. Furthermore, higher concentrations of TCS were observed in areas that are more impacted by human activities. There was a significant positive correlation between TCS and nitrogen in the surface water. A risk assessment using the risk quotient (RQ) method showed that a potentially high risk (RQ ​> ​1) was found only in surface waters from Donghu Lake, and that the sediments posed a lower risk than the surface waters. These results provide timely data on the temporal and spatial occurrence of TCS in freshwater lakes in China following the outbreak of COVID-19 and demonstrate a possible high risk of exposure to TCS for aquatic biota

Uptake, accumulation, and degradation of dibutyl phthalate by three wetland plants

The uptake and degradation mechanisms of dibutyl phthalate (DBP) by three wetland plants, namely Lythrum salicaria, Thalia dealbata, and Canna indica, were studied using hydroponics. The results revealed that exposure to DBP at 0.5 mg/L had no significant effect on the growth of L. salicaria and C. indica but inhibited the growth of T. dealbata. After 28 days, DBP concentrations in the roots of L. salicaria, T. dealbata, and C. indica were 8.74, 5.67, and 5.46 mg/kg, respectively, compared to 2.03–3.95 mg/kg in stems and leaves. Mono-n-butyl phthalate concentrations in L. salicaria tissues were significantly higher than those in the other two plants at 23.1, 15.0, and 13.6 mg/kg in roots, stems, and leaves, respectively. The roots of L. salicaria also had the highest concentration of phthalic acid, reaching 2.45 mg/kg. Carboxylesterase, polyphenol oxidase, and superoxide dismutase may be the primary enzymes involved in DBP degradation in wetland plants. The activities of these three enzymes exhibited significant changes in plant tissues. The findings suggest L. salicaria as a potent plant for phytoremediation and use in constructed wetlands for the treatment of DBP-contaminated wastewater. HIGHLIGHTS The uptake and degradation mechanisms of DBP by three common wetland plants were investigated by the hydroponic experiment.; The uptake and degradation capacities of DBP were higher in L. salicaria, which could well resist the oxidative damage caused by DBP and degrade it under the effect of enzymes.; L. salicaria can be used as a potential plant for DBP removal in phytoremediation and the constructed wetland.

Treatment performance and microbial response to dibutyl phthalate contaminated wastewater in vertical flow constructed wetland mesocosms

Phthalic acid esters (PAEs), especially dibutyl phthalate (DBP) pollution in the environment, have attracted worldwide attention. Four Phragmites australis-based, mesocosm-scale vertical flow constructed wetlands (VFCWs) with different hydraulic loading rates (HLRs) were operated for one year to study the removal efficiency and mechanisms of DBP in the reclaimed water. The average removal efficiencies for DBP were 93.77 +/- 3.27%, 94.9 +/- 2.60% and 97.0 +/- 3.00% in the VFCWs under HLRs of 0.33, 0.22 and 0.11 m/d, respectively. DBP can be accumulated and degraded by wetland plants and its concentration in the roots (0.256-8.45 mg/kg) were higher than in the leaves (0.243-0.482 mg/kg). The concentrations of primary and secondary metabolites mono-n-butyl phthalate (MBP) and phthalic acid (PA) were 0.142 -2.35 mg/kg and 0.113-0.545 mg/kg respectively in the plant tissues. The concentrations of DBP were 38.2-271 mu g/kg in the substrates. Mass balance for DBP indicates that the estimated plant uptake and substrate adsorption of total DBP is negligible. This suggests that biodegradation and other process are the primary pathways for DBP removal in VFCWs. The results of 16S rDNA and ITS rDNA high-throughput sequencing indicated that both bacterial and fungal community diversity decreased with the exposure of DBP. Janthinobacterium, Flavobacterium and Curvularia genera may be the main participants in the biodegradation of DBP in the CWs. (C) 2019 Elsevier Ltd. All rights reserved