(24, 25) Alternative adsorbents have also been explored, including carbonaceous resins, high-silica zeolites, fly ash, chitosan, ore minerals, multiwalled carbon nanotubes, and synthetic polymer resins. But SPAC also interacts rapidly with NOM which limits MP adsorption capacity in natural waters. (25) The increased surface area of SPAC can greatly improve the kinetics of MP adsorption. For example, superfine powdered activated carbon (SPAC) has been explored as a means to accelerate adsorption processes in drinking water (24) and wastewater treatment. Adsorption kinetics have been recognized as an essential property that influences adsorbent doses, required contact times, and consequently the life-cycle costs and throughput of adsorption treatment processes. Several studies have focused on improving the efficiency of adsorption processes designed for MP removal. (12) Further complications of AC adsorption arise from relatively slow adsorption kinetics, (19-21) poor affinity for polar MPs, (22) and the tendency to be fouled by natural organic matter (NOM) and other matrix constituents.
(12) However, AC adsorption processes are more expensive than advanced oxidation because of the large carbon doses needed to achieve similar treatment goals and the energy requirements of AC recovery and regeneration. (12) AC adsorption completely removes MPs without forming oxidized byproducts, resulting in a greater reduction in residual toxicity. (16-18) AC adsorption processes also remove MPs effectively, and powdered activated carbon processes have become favored for water and wastewater treatment. (14, 15) Advanced oxidation processes reduce MP loads but are energy intensive, rely on chemical reagents, and may form oxidation products that retain toxic activity. Advanced oxidation and activated carbon (AC) adsorption have attracted the most attention because of their technological and economic scalability, (12, 13) though membrane filtration and reverse osmosis have also been considered. (10, 11) This deficiency has motivated the development of advanced treatment processes to remove MPs during water or wastewater treatment. These data highlight advantages of P-CDP adsorbents relevant to MP removal during water and wastewater treatment.Ĭonventional water and wastewater treatment processes do not adequately remove many polar and semipolar MPs. P-CDP performed particularly well for positively charged MPs and neutral or negatively charged MPs with McGowan volumes greater than 1.7 (cm 3 mol –1)/100. Increasing ionic strength and the presence of NOM had a negative effect on the adsorption of MPs to CCAC but had almost no effect on adsorption of MPs to P-CDP. The extent of MP removal demonstrates slower but more uniform uptake on CCAC and faster but more selective uptake on P-CDP. Data reveal pseudo-second-order rate constants for most MPs ranging between 1.5 and 40 g mg –1 min –1 for CCAC and 0 g mg –1 min –1 for P-CDP. Performance was benchmarked against a coconut-shell activated carbon (CCAC). Adsorption kinetics and MP removal were measured in batch and flow-through experiments for a mixture of 83 MPs at environmentally relevant concentrations (1 μg L –1) and across gradients of pH, ionic strength, and natural organic matter (NOM) concentrations.
The objective of this research was to evaluate the performance of porous β-cyclodextrin polymers (P-CDP) as adsorbents of MPs in aquatic matrixes. Your display size and text preferences will reset to the original setting of your device.The cost-effective and energy-efficient removal of organic micropollutants (MPs) from water and wastewater is challenging. Tip: You will find a preview of the change of your font and display sizes after you've set each slider to your preferred size and if you don't like it, to reset your settings, tap Reset settings. To change your preferred display size, move the slider left or right.To make your display size smaller or larger: To change your preferred font size, move the slider left or right.To make your font size smaller or larger: Important: The font size setting doesn't apply to some apps. Tip: These settings can also be set up from the start in the setup wizard. You can also find accessibility settings in quick settings, where you can quickly change your preferred text and content settings.
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