The Influence Of Desorption Behavior On PPCPs In The Weihe Riverbed’s Sediments By The Humic Acid Colloid

Pharmaceuticals and personal care products(PPCPs) are emerging contaminants, have received abroad concerns, due to some substances can lead to "three-induced effect". As a claas of contaminants, antibiotics and anti-inflammatory drugs are detected in the higher frequencies. Riverbed sediments is important solute transport medium, the adsorption/desorption behavior of pollutants directly affect the characteristics of contaminant migration. Adsorption process inhaled pollutants in sediments from the river, so that a certain degree of sediment contamination, may also cause secondary pollution; desorption sucked sediment contaminants released, so that these are desorbed get a lot of pollutants in water diluted to reduce pollution levels, and the extent of contaminated sediment has also been a corresponding relief.Weihe river as the largest tributary of the Yellow River and the most important river in Weibei plain. Some scholars of the Weihe river sediments florfenicol, PAHs, organochlorine pesticides, oxytetracycline and acetaminophen and other organic pollutants the adsorption behavior was studied extensively, but the Weihe river sediments oxytetracycline and acetaminophen desorption behavior has not made some insights. Therefore, the study of substances desorption behavior of PPCPs in the Weihe river sediments for a better understanding of their migration in the Weihe river, the transformation, fate is extremely important for the effective prevention of pollution of the Weihe river PPCPs substances to ensure the safety of surface groundwater provided theoretical basis and reference.We select the middle reaches of the Weihe river farmhouse、livestock and other pollution sources of PPCPs as typical area of the study, with antibiotic oxytetracycline(OTC) and anti-inflammatory drugs in acetaminophen(APAP) as the target contaminants, from the presence or absence of humic acid colloids angle by batch equilibrium method systematically studied the Weihe river sediments of these two target contaminant desorption kinetics and thermodynamics of the characters of the targets deposited in the Weihe river desorption mode and mechanism on the matter. This research has acquired following conclusions:1. OTC and APAP desorption equilibrium is reached in 20 min basically, and this process is in line with the pseudo-second-order kinetic model. Different temperature has a great influence on the desorption behavior of OTC and APAP. Elevated temperatures will inhibit the desorption process.2. OTC and APAP desorption process is not only a spontaneous and exothermic reactions, but also the process of entropy increase, the degree of disorder from disorder to order.3. Onic strength increases will inhibit the desorption process of OTC and APAP.4. The desorption of OTC and APAP has some differences, which may be related to both the internal structure(such as a functional group, etc.).5. It showed that adding humic acid colloid can delay the desorption of OTC and APAP in sediment and to reach equilibrium at 30 minutes. Desorption kinetics model conforms to the pseudo-second-order kinetic model. Meanwhile, elevated temperature is not conducive to the desorption process.6. Humic acid colloids inhibit the desorption behavior of OTC and APAP, and delay the desorption equilibrium time, resulting in significantly lower desorption.