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The main goal of this study is the examination of polypropylene (PP) microplastics (MPs) as possible carriers of daily use pharmaceutical compounds. The selected compounds can be separated into three groups: (i) antibiotics (Trimethoprim, Metronidazole, Indomethacin, Isoniazid), (ii) anti-inflammatories (Ketoprofen, Diclofenac), and (iii) anti-hypertensive (Valsartan). Two types of PP MPs (virgin and UV-aged) were used in the experimental procedure, and the effect of time and the effect of the initial concentrations of the drugs were examined. The impact of various environmental factors such as pH, salinity, and natural organic matter were also explored. The last two factors were studied using real aqueous matrices such as wastewater and seawater. According to the obtained results, the highest uptake was observed in indomethacin (9.3 mg/g) and diclofenac (7.3 mg/g), owing to their physiochemical properties. Aged particles showed enhanced adsorption ability in accordance with the existing literature, as their adsorption capacity was between 0.5–1.5 times greater than that of the virgin ones. Regarding the desorption of compounds from the virgin and aged PP MPs at three different pH values, diclofenac and indomethacin exhibited the highest desorption capacity, while alkaline conditions favored the desorption ability of PP MPs for most of the target compounds. [ABSTRACT FROM AUTHOR]

This article presents styrene–divinylbenzene copolymers that contain aminophosphinic acid groups, used to remove acetylsalicylic acid (AS). The chemically modified copolymers were obtained using phenylphosphinic acid and propylamine (AAP1), benzylamine (AAP2) and, respectively, butylamine (AAP3) by the "one-pot" Kabachnik–Fields synthesis. The obtained adsorbents were characterized by FT-IR spectroscopy, thermogravimetric analysis, SEM/EDX analysis and statistical modeling of the repetitive unit. The weight loss of the samples, when analyzed in a nitrogen atmosphere and at 800 °C, was the following: AAP1: 58.71%; AAP2: 59.52%; and for AAP3: 59.66%. The adsorption process at equilibrium was modeled by the Langmuir, Freundlich, Sips and Redlich–Peterson adsorption isotherms. The maximum adsorption capacity given by the Langmuir isotherm was influenced by the amine used in the synthesis of sorbent. The best results were obtained at 298 K, with a maximum adsorption capacity of 0.236 mmol/g (42.52 mg/g) on the copolymer AAP1. The adsorption process was fast, over 85% of the maximum adsorption capacity being achieved in the first 4 h. The adsorption of AS on the studied adsorbents is an exothermic and thermodynamically favorable process. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), chlorinated phenols (CPs), polycyclic aromatic hydrocarbons (PAHs) and halogenated benzenes (HBs) are pollutants that are widely present in freshwater systems. As alternatives to conventional plastics, bioplastics are receiving a lot of attention, but there are limited data on their impact on pollutant behavior. This work therefore investigated the impact of pH on the sorption of CPs, PAHs and HBs, as some of the toxic and highly persistent pollutants, on seven different plastics using kinetic and isotherm studies. The pH of the water matrix impacted the adsorption behavior of CPs on all selected MPs, with the highest degree of adsorption occurring at pH 7 for the majority of the selected CPs. The highest adsorption affinity of CPs on the MPs, at pH 7, was obtained for 4-chlorophenol and 2,4-dichlorophenol on powdered polyethylene standard (qt = 221 μg/g), while the lowest was obtained for the adsorption of pentachlorophenol on polyethylene terephthalate (qt = 25 μg/g). On the other hand, the pH value of the water matrix did not affect the adsorption of halogenated benzenes and PAHs on MPs. The pseudo-second-order rate model fit the adsorption kinetics data of all experiments. The results obtained for the adsorption of CPs on MPs indicated a lower sorption affinity of CPs with MPs at pH 4 and pH 10 compared to pH 7. The Langmuir isotherm, at pH 7, implied that 4-chlorophenol's adsorption affinity was not significantly influenced by the type of MPs. On the other hand, at pH 7, the adsorption of 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol varied greatly, with powdered MP types showing the highest affinity for CP adsorption. Furthermore, the obtained adsorption isotherm results imply that electrostatic attraction, hydrogen bonds, π-π interactions and van der Waals interactions, are an integral part of adsorption mechanisms of the CPs on the MPs. [ABSTRACT FROM AUTHOR]

Pharmaceuticals and microplastics have long been identified as water pollutants. Pollutants, including pharmaceutical compounds, have been shown to be transported by microplastics (MPs). In this mini-review, adsorption mechanism between microplastics and emerging contaminants were highlighted. Polyethylene is a non-polar, semi-cystalline microplastic with a density of 240 to 244 kg/m³. Besides, Ibuprofen adsorption onto microplastics is pH dependent. Non-polar or neutral compounds that are homogeneous and extremely hydrophobic in nature interact with non-polar and weakly polar plastics such as Polypropylene and Polyethylene. Furthermore, Molecular dynamic (MD) simulation can be employed to study the mechanism of interaction between MPs and contaminants. As a result, some studies show a complex interaction between polyethylene (PE) and certain contaminants, with no significant differences in adsorption energies, but sulfamethazine molecules effectively adsorbed on the MPs surface. In summary, this mini review shed lights on the insights of adsorption mechanism between these compounds. [ABSTRACT FROM AUTHOR]

The combined pollution of microplastics (MPs) and antibiotics in the water environment has received much attention in the past decade. MPs are often considered ideal adsorption carriers for organic matter (OM) in the water environment. Meanwhile, mechanical wear and ultraviolet radiation will make MPs age and enhance the adsorption of OM on MPs. In this study, biodegradable polylactic acid (PLA), non-biodegradable polyethylene terephthalate (PET), and polypropylene (PP) were aged by K2S2O8 advanced oxidation. The adsorption behavior of MPs before and after aging to norfloxacin antibiotic (NOR) was studied. Results showed that the surface of MPs after aging had cracked and become rougher. The aged PLA was the most changed among the three kinds of aged MPs, and its specific surface area, equilibrium, and saturated adsorption capacity of aged PLA reached 15.826 m2/g, 1.184 mg/g, and 15.241 mg/g, respectively. Most of the adsorption of NOR on pristine and aged MPs was more aligned with the pseudo-first-order. The NOR was multiple adsorptions on the surface of aged PLA and aged PET, while it was monolayer adsorption on the surface of aged PP. In addition, it was different for the effect of pH, salinity, and dissolved organic matter (DOM) on the adsorption of NOR on different MPs. These results suggested that the chemical aging of MPs can enhance the adsorption capacity of MPs to NOR and promote the carrier effect of it to NOR. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), as vectors for various pollutants in the environment, have been arousing public concern in recent years. The extensive use of antibiotics has led to their frequent detection in water environments, where they inevitably coexist with MPs and are actively adsorbed onto MPs' surfaces. However, the information on the influence of the main environmental factors on the sorption behavior of MPs is not fully understood, and especially, information about the effect mechanism is limited. This study aims to comprehensively assess the main factors and mechanisms that affect antibiotic sorption onto microplastics. The results indicated that the adsorption of tetracycline (TC) onto PVC MPs fits the pseudo-second-order model well. The adsorption of TC onto PVC MPs decreased with increasing salinity and pH. With the help of SED analysis, the decrease at high salinity was attributed to the decreased quantities of the most distributed energy sites in high-salinity systems compared to freshwater. Additionally, the decreased adsorption capacity of TC onto MPs at high pH mainly resulted from the electrostatic repulsion between MPs and TC2−. The coexisting Cu2+ and TC could improve the affinity between PVC MPs and TC via "MPs-TC-Cu2+" and "MPs-Cu2+-TC" bridges, boosting the capacity of PVC MPs to adsorb TC. This study provides comprehensive insights into the influence and mechanism of the main factors on the environmental behaviors of the coexistence of MPs with antibiotics, which is of great importance for evaluating and controlling their risks. [ABSTRACT FROM AUTHOR]

The use of clays as adsorbents and catalysts in the ozonation of organic pollutants (Atrazine, bis-Phenol A, Diazinon, and Diclofenac sodium) allowed simulating their natural oxidative degradation in clay soils and to evaluate the ecotoxicity of mixtures partially oxidized on the species Lemna minor, a biodiversity representative of plants in the aquatic environment. Kinetic data showed that the adsorption of organic pollutants on clay particles obeys the pseudo-second-order model, while the adsorption isotherms satisfactorily fit the Langmuir model. Adsorption reduces the dispersion of the organic pollutant in the environment and prolongs its persistence and its natural degradation probability. Measurements of the Zeta potential and particle size as a function of pH demonstrate that the catalytic activity of clay depends on its cation, its silica/alumina ratio, and therefore on its permanent and temporary ion exchange capacities. These factors seem to govern its delamination and dispersion in aqueous media, its hydrophilic-hydrophobic character, and its porosity. Tests conducted on Lemna minor in contact with ozonation mixtures revealed that the toxicity could be due to pH decrease and to the toxicity of the intermediates yielded. Ecotoxicity would depend on the structure of the organic molecules, the chemical composition of the clay surface and ozonation time, which determines the oxidation progress. These results are of great importance for further research because they allow concluding that the negative impact of the persistence of an organic molecule in clay-containing media depends on the type and composition of the very clay mineral. [ABSTRACT FROM AUTHOR]

The presence of microplastics (MPs) in the environment, and the effects that the ingestion of these materials can have on organisms, can be aggravated by the adsorption of harmful substances on the surface or inside the MPs. Of special relevance are the studies that have been carried out on the adsorption and transport of polycyclic aromatic hydrocarbons (PAHs) as well as persistent organic pollutants (POPs) such as dioxins and furans (PCDD/Fs). This review will delve into the research carried out to date regarding the adsorption by conventional and biodegradable MPs of dangerous organic compounds such as those mentioned. In general, the presence of MPs is considered a vector for the entry of these contaminants into living beings, since their capacity to adsorb contaminants is very high and they are ingested by different organisms that introduce these contaminants into the trophic chain. [ABSTRACT FROM AUTHOR]

Microplastics (MP) are spread into all ecosystems and represent a threat to the equilibrium of the environment and human health, not only due to their intrinsic characteristics but also to their action as effective carriers of contaminants, such as pesticides, pharmaceuticals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons. The pesticide α-endosulfan is persistent and spread in the environment. The MP are another possible way of dissemination to be considered in the fate of this pesticide. The adsorption dynamics of α-endosulfan by six different MP (low-density polyethylene—LDPE, polyethylene-co-vinyl acetate, unplasticized polyvinyl chloride, polyamide 6, polystyrene granule, polypropylene granule) with different sizes/shapes and chemical compositions were evaluated. The most critical situation was identified for the system LDPE (particle size < 300 μm). Equilibrium studies (48 h equilibrium time) were performed for distilled, tap and filtered river water. Based on the Langmuir model parameters, the highest maximum adsorption capacity was obtained for distilled water, followed by filtered river and tap waters (i.e., 366 ± 39, 247 ± 38, 157 ± 22 μg/g). The obtained results demonstrate the important role that microplastics may have in the fate and transport of pesticides and their potentially harmful effect on the environment, which requires further investigation. [ABSTRACT FROM AUTHOR]

Pharmaceutical products have become a necessary part of life. Several studies have demonstrated that indirect exposure of humans to pharmaceuticals through the water could cause negative effects. Raw sewage and wastewater effluents are the major sources of pharmaceuticals found in surface waters and drinking water. Therefore, it is important to consider and characterize the efficiency of pharmaceutical removal during wastewater and drinking-water treatment processes. Various treatment options have been investigated for the removal/reduction of drugs (e.g., antibiotics, NSAIDs, analgesics) using conventional or biological treatments, such as activated sludge processes or bio-filtration, respectively. The efficiency of these processes ranges from 20–90%. Comparatively, advanced wastewater treatment processes, such as reverse osmosis, ozonation and advanced oxidation technologies, can achieve higher removal rates for drugs. Pharmaceuticals and their metabolites undergo natural attenuation by adsorption and solar oxidation. Therefore, pharmaceuticals in water sources even at trace concentrations would have undergone removal through biological processes and, if applicable, combined adsorption and photocatalytic degradation wastewater treatment processes. This review provides an overview of the conventional and advanced technologies for the removal of pharmaceutical compounds from water sources. It also sheds light on the key points behind adsorption and photocatalysis. [ABSTRACT FROM AUTHOR]

Olive pomace (OP) is an agricultural by-product of the olive oil production process. Olive oil mills generate a huge amount of OP that has adverse impacts on the environment due to its phytotoxic properties. Therefore, the utilization of OP in the production of activated carbon may be considered as an alternative eco-friendly solution for disposal and recycling of this waste. The adsorption of sulfadiazine (SDZ), an antibiotic of the sulfonamide group, using activated carbon from olive pomace (OPAC) was investigated under different experimental conditions. The characterization of synthesized activated carbon samples was performed by elemental analysis, BET surface area, total pore volume, average pore size, pHpzc, FTIR, and SEM-EDX analysis. In batch experiments, the effects of adsorption parameters such as pH of the solution, contact time, activated carbon dosage, initial SDZ concentration, and temperature were assessed. The results showed that the pH of the solution slightly affected the SDZ adsorption capacity of OPAC. In order to express the adsorption behavior of SDZ onto OPAC, Langmuir, Freundlich, Dubinin–Radushkevich (D–R), and Temkin isotherm models were applied to the experimental equilibrium data. The maximum adsorption capacity calculated from the Langmuir isotherm was 66.2252 mg/g at 298 K. The data from kinetic studies were analyzed using pseudo-first-order and pseudo-second-order models. The results indicated that the adsorption process of SDZ onto OPAC followed the pseudo-second-order model rather than the pseudo-first-order model. Based on the thermodynamic parameters including ΔG0, ∆H0, and ∆S0, it can be concluded that the nature of the adsorption process is exothermic, spontaneous, and favorable and of increased disorder and randomness. This work demonstrates that OP can be used as a precursor for activated carbon production and may substitute with commercial activated carbon for the removal of antibiotics from aqueous media. The production of activated carbon from OP will provide both minimization and recovery of this waste. [ABSTRACT FROM AUTHOR]

Large quantities of antibiotics are manufactured, used, and eventually discharged into alga-containing water environment as prototypes, by-products, or transformation products. Different activities of Chlamydomonas reinhardtii toward cefradine (CFD) were studied, and the results indicated that CFD is resistant (removal rate of 5.45–14.72%) in simulated natural water environment. Cefradine was mainly removed by hydrolysis, adsorption, desorption, photodecarboxylation, and photoisomerization. The effects of C. reinhardtii density, initial solution pH, and different light sources on CFD removal efficiency were investigated. The optimum conditions occurred at a density of algae 10 × 104 cells/mL, a solution pH of 9.0, and the ultraviolet (UV) light. Additionally, the removal kinetics under 16 different conditions was explored. The results showed that the removal of CFD fits well with a pseudo-first-order kinetic, and the half-life times are from 0.8 to 261.6 days. This study summarizes the CFD removal mechanisms in alga-containing water environment, highlights the important role played by light irradiation in eliminating CFD, and obtains the important kinetic data on CFD removal. [ABSTRACT FROM AUTHOR]

As a nano-adsorbent, magnetic graphene oxide (GO/Fe3O4) was synthesized to potentially adsorb propranolol (PRO) from water. The synthetic material was characterized by SEM, TEM, VSM, FTIR, XRD, zeta potential, and XPS. The environmental factors, such as pH, humic acid concentration, PRO concentration, and contact time, were investigated regarding their effect on the adsorption process. The kinetics data fitted the pseudo first-order and second-order kinetics equations. The Langmuir equation, the Freundlich equation, and the Sips equation were used to analyze the adsorption isotherms. Electrostatic attraction, hydrogen bonding, and the π–π interaction all contributed to the adsorption process of PRO onto GO/Fe3O4. The discovery of this study emphasized the feasibility of GO/Fe3O4 removal of PRO and expanded the scope of the application of GO. [ABSTRACT FROM AUTHOR]

In this work, a novel adsorbent attapulgite/graphene oxide magnetic composite (ATP/Fe3O4/GO) was synthesized for removing propranolol (PRO) from aqueous water. The factors affecting the PRO adsorption process onto ATP/Fe3O4/GO including pH, ionic strength, sorbent dosage, and humic acid were systematically investigated by batch experiments. Meanwhile, magnetic attapulgite (ATP/Fe3O4) and magnetic graphene oxide (GO/Fe3O4) were prepared for the comparison of the adsorption performance for PRO. The structural and surface characteristics of the resulting materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential measurements, and scanning electron microscope. The results showed that the adsorption rate of PRO onto ATP/Fe3O4/GO was up to 99%, faster and higher than that of other adsorbents involved at neutral pH. Moreover, the adsorption kinetics were better fitted with pseudo-first-order kinetic model than the second-order kinetic model. The adsorption data were fitted well with the Freundlich isotherm equations, implying that the adsorption process was heterogeneous. The adsorption reaction was endothermic and spontaneous according to the thermodynamic parameters. All results indicated that ATP/Fe3O4/GO was a promising adsorbent for removing PRO from water. [ABSTRACT FROM AUTHOR]