Suchergebnisse

AbstractPoly‐ and perfluoroalkyl substances (PFAS) are known as "forever chemicals" due to their ubiquitous persistence in the environment, and their negative human health effects. Among them, short‐chain PFAS are of increasing concern due to their high solubility and mobility in water, while possessing persistency and toxicity nature like their longer‐chain analogs. The most common method for PFAS removal from water is by sorption with activated carbons or ion exchange resins, but these adsorbents only exhibit limited removal efficiency against short‐chain PFAS, and they require frequent replacement leading to high operational cost. Here we review and discuss the potential of using bio‐adsorbents, which can be derived from common biomass feedstocks, as low‐cost alternatives to traditional adsorbents, while these materials can also possess good removal efficiency against short‐chain PFAS. We further provide the perspective on the designs of low‐cost, activated bio‐adsorbent systems that can be implemented for effective removal of short‐chain PFAS.

AbstractThe presence of pharmaceutical pollutant, doxycycline (DOC) in water and waste streams has negative impact on the environment. In this research, metal organic framework was synthesized and functionalized by potassium nickel ferrocyanide (KNiFC). After characterisation, the functionalized adsorbent was used for removal of DOC from aqueous solutions. The adsorbent containing 80% of KNiFC exhibited the high adsorption capacity of 100 mg/g. The adsorption process was kinetically fast and the equilibration was established within 30 min. The used adsorbent retained 90% of its initial capacity after regeneration. The magnetic susceptibility of the adsorbent measured by VSM technique was 35 emu/g and sufficient for separation of the used adsorbent by external magnetic field. Isotherm models including Langmuir, Freundlich, Tempkin, Redlich‐Peterson, and Sips were applied to correlate the experimental equilibrium data. To evaluate the fitness of the isotherm equations error analysis methods, residual root mean square error and average relative error were used.

In this work, novel Sodium benzyl sulfonate functionalized-bentonite (SBSB) adsorbent was synthesized through the reaction of bentonite with benzyl alcohol and chlorosulfonic acid. The prepared adsorbent was characterized using Low-angle XRD, FT-IR and TGA methods, and applied for the removal of calcium and magnesium ions from water solutions. The effect of contact time and initial hardness concentration on the hardness removal efficiency of the prepared adsorbents were studied. It was found that the adsorption was reached the equilibrium condition within about 60 min, and the maximum adsorption capacity (52.5 mg g−1) was achieved in the hardness of 150 mg L−1. Compared to pristine bentonite, the adsorption efficiency of SBSB was significantly enhanced, which is ascribed to the presence of benzyl sulfonate functional groups on its surface. The adsorption isotherm of calcium and magnesium ions on SBSB was described by Langmuir and its adsorption kinetic behavior followed pseudo-second-order model.