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Reverse osmosis (RO) and nanofiltration (NF) are effective technologies for removing organic compounds from water. Most research focuses on the removal of organic compounds from water already treated. However, evaluating their removal from groundwater is necessary because coexisting ions affect treatment efficiency. In the case of inorganic compounds, the water's pH, concentration, and membrane charge are the main factors affecting the electrostatic repulsion between the ionic compounds and the charged membrane. This study aims to present the efficiency of removing the studied compounds with NF/RO from groundwater and the physicochemical and chemical processes involved in the removal. As a result of the research, it is found that the hydraulic performance of the membrane, especially for RO, is stable; the efficiency of benzene, ethylbenzene, toluene, and o-, m-, p-xylene removal throughout the research process is at 86% for RO and about 65% for NF. [ABSTRACT FROM AUTHOR]

We classify bisphenols as organic compounds from the group of phenols. Since bisphenols are carcinogenic and disrupt the human body's hormonal balance, removing these compounds from the aquatic environment is crucial. The production of creams and household plastics uses bisphenols. Such harmful compounds include bisphenol A and its derivatives (e.g., bisphenol B (BPB), bisphenol AP (BPAP), bisphenol M (BPM), bisphenol E (BPE), and bisphenol C (BPCl2)). Although bisphenol A is still the dominant bisphenol in the environment, the legal restrictions on its use lead to the use of other bisphenols. Biochemical processes remove 50%--90% of these compounds from wastewater. Introducing Fenton's reagent or UV radiation improves efficiency. However, these are still ineffective methods of their removal from sewage and water. The paper focuses on the possibility of removing bisphenols: bisphenol A, bisphenol E, bisphenol B, bisphenol G, bisphenol C, bisphenol AP, and bisphenol M from surface water using integrated nanofiltration--reverse osmosis membrane processes. The research is carried out at a small nanofiltration and reverse osmosis station. The process uses nanofiltration and the osmotic membrane of spiral aromatic polyamide membranes. Chemical determinations are made by chromatographic analysis developed for these compounds. The conducted studies showed the removal of the tested compounds with high effectiveness. The process parameters significantly influence the removal process, particularly the concentration of bisphenols in the feed and the transmembrane pressure. The impact of these processes should be further analyzed and explained. [ABSTRACT FROM AUTHOR]

Benzotriazoles (BTs) harm the life of organisms due to their chemical, physical and biological properties. It is essential to remove them from the natural environment without introducing additional chemical compounds into it. Benzotriazoles are difficult to remove from water because they are resistant to classic technological processes used for water treatment, for example, chlorination, biodegradation, or ozonation. To extend the methods of removing benzotriazoles from water, a membrane process was used – nanofiltration. The research was carried out at a small nanofiltration station with a spiral aromatic polyamide membrane. Four compounds were selected for the study: 1H-benzotriazole (BT), 4-methyl-1H-benzotriazole (4MBT), 5-methyl-1H-benzotriazole (5MBT), and 5-chlorobenzotriazole (5ClBT). The tests were carried out using surface water enriched with a standard solution of the tested compounds. As a result of the research carried out at this stage, data were obtained which indicate the dependence of the treatment efficiency on the transmembrane pressure. [ABSTRACT FROM AUTHOR]

Pressure membrane processes such as nanofiltration (NF) play an important role in purifying water, from which not only inorganic substances but also petroleum-derived organic compounds can be removed. The study evaluated the removal of petroleum hydrocarbons from water using nanofiltration. The work was carried out applying a spiral module equipped with a commercial NF-212 membrane. Model water was used for the study. Determinations of studied petroleum aliphatic hydrocarbons from C7 to C33 and monoaromatic hydrocarbons were performed on a gas chromatograph coupled with a mass spectrometer. Quantitative analysis was performed using the calibration curve method. During the process, the retention factor, volumetric flow of deionized water (Jw), both before and after the process and volumetric flow of model water permeate were calculated, and the relative membrane permeability value for the deionized water stream aw and the relative membrane permeability for the model water stream av was calculated. [ABSTRACT FROM AUTHOR]