Synthesis of novel magnetic pitch-based hypercrosslinked polymers as adsorbents for effective recovery of Ag+ with high selectivity

Construction of carboxyl-functionalized hyper-cross-linked porous polymers using waste polystyrene for effective adsorption of phenolic contaminants

The extensive presence of phenolic organic contaminants (POCs) poses a serious threat to humans. Meanwhile, the upcycling/reusing of waste polystyrene to reduce the exponential growth of plastic pollution is a very important environmental issue. Addressing these demands, a series of carboxyl-functional hypercrosslinked polymers (labeled PP-HCPs) were constructed by knitting waste polystyrene with pyromellitic dianhydride at different ratios through a one-step Friedel-Crafts reaction for effective adsorption of POCs. Among the prepared PP-HCPs, PP-HCP2 displayed a large specific surface area with high adsorption capacity (37.3 mg g-1) for POCs. Using PP-HCP2 as solid phase extraction sorbent, six POCs were effectively extracted from water and peach drink samples, then subjected to high-performance liquid chromatography-ultraviolet detection. The method demonstrated good linearity in the range of 0.03-100.0 ng mL-1 for water samples and 0.06-100.0 ng mL-1 for peach drinks under optimum experimental conditions. At a signal-to-noise ratio of 3, low detection limits were found to be 0.01-0.10 ng mL-1 for water samples and 0.02-0.15 ng mL-1 for peach drinks. Good accuracy and repeatability were achieved with recoveries of 85.3-111.8 % and the relative standard deviations below 8.6 %. The PP-HCP2-based approach can be employed as a dependable and sensitive tool to detect POCs in water and peach drink samples. This work delivers a simple and economically viable approach to fabricate carboxyl-functional HCPs by converting waste foam into high-value-added sorbent, with great significance for sustainable development.

Uniform phosphazene containing porous organic polymer microspheres for highly efficient and selective silver recovery

The efficient extraction of silver ions (Ag+) from Ag+-contaminated wastewater is crucial for resource recovery and environmental protection. However, the synthesis of adsorbents with high adsorption capacity and superior selectivity for Ag+ is a significant challenge. Herein, a series of phosphazene-based porous organic polymers (POPs) microspheres with exceptional selectivity and adsorption capacity for Ag+ were rationally designed using phosphazene and aromatic amines. Notably, variations in the types of precursors induced the formation of a microsphere-like morphology with precisely controlled surface smoothness. Considering the advantages of abundant heteroatom active sites, surface charge properties and microsphere-like morphology, the synthesised networks exhibited an exceptional Ag+ adsorption capacity of 818.3 mg/g in aqueous solution at 45 °C, showcasing remarkable selectivity (selectivity coefficient (Kα) 3.39 × 105) and an ultrafast adsorption rate, adsorbing Ag+ in just 5 min. These superior adsorption characteristics surpassed those of most reported POPs. Theoretical simulations further revealed that key structural motifs, particularly phosphazene units, played a critical role in enhancing Ag+ adsorption. This study proposes a promising strategy for the efficient recovery of Ag from wastewater using high-performance porous adsorbents.

Synthesis and Characterization of Maghemite Nanoparticles Functionalized with Poly(Sodium 4-Styrene Sulfonate) Saloplastic and Its Acute Ecotoxicological Impact on the Cladoceran Daphnia magna

Using a modified co-precipitation method, 11(2) nm γ-Fe2O3 nanoparticles functionalized with PSSNa [Poly(sodium 4-styrenesulfonate)] saloplastic polymer were successfully synthesized, and their structural, vibrational, electronic, thermal, colloidal, hyperfine, and magnetic properties were systematically studied using various analytic techniques. The results showed that the functionalized γ-Fe2O3/PSSNa nanohybrid has physicochemical properties that allow it to be applied in the magnetic remediation process of water. Before being applied as a nanoadsorbent in real water treatment, a short-term acute assay was developed and standardized using a Daphnia magna biomarker. The ecotoxicological tests indicated that the different concentrations of the functionalized nanohybrid may affect the mortality of the Daphnia magna population during the first 24 h of exposure. A lethal concentration of 533(5) mg L-1 was found. At high concentrations, morphological changes were also seen in the body, heart, and antenna. Therefore, these results suggested the presence of alterations in normal growth and swimming skills. The main changes observed in the D. magna features were basically caused by the PSSNa polymer due to its highly stable colloidal properties (zeta potential > -30 mV) that permit a direct and constant interaction with the Daphnia magna neonates.

Recovery of Ag(I) from Wastewater by Adsorption: Status and Challenges

Untreated or inadequately treated silver-containing wastewater may pose adverse effects on hu-man health and the ecological environment. Currently, significant progress has been made in the treatment of Ag(I) in wastewater using adsorption methods, with adsorbents playing a pivotal role in this process. This paper provides a systematic review of various adsorbents for the recovery and treatment of Ag(I) in wastewater, including MOFs, COFs, transition metal sulfides, metal oxides, biomass materials, and other polymeric materials. The adsorption mechanisms of these materials for Ag(I) are elaborated upon, along with the challenges currently faced. Furthermore, insights into optimizing adsorbents and developing novel adsorbents are proposed in this study.

Elimination of Pharmaceutical Compounds from Aqueous Solution through Novel Functionalized Pitch-Based Porous Adsorbents: Kinetic, Isotherm, Thermodynamic Studies and Mechanism Analysis

The long-term presence of PPCPs in the aqueous environment poses a potentially significant threat to human life and physical health and the safety of the water environment. In our previous work, we investigated low-cost pitch-based HCP adsorbents with an excellent adsorption capacity and magnetic responsiveness through a simple one-step Friedel-Crafts reaction. In this work, we further investigated the adsorption behavior of the prepared pitch-based adsorbents onto three PPCP molecules (DFS, AMP, and antipyrine) in detail. The maximum adsorption capacity of P-MPHCP for DFS was 444.93 mg g-1. The adsorption equilibrium and kinetic processes were well described through the Langmuir model and the proposed secondary kinetic model. The negative changes in Gibbs free energy and enthalpy reflected that the adsorption of HCPs onto PPCPs was a spontaneous exothermic process. The recoverability results showed that the adsorption of MPHCP and P-MPHCP onto DFS remained above 95% after 10 adsorption-desorption cycles. The present work further demonstrates that these pitch-based adsorbents can be used for multiple applications, which have a very extensive practical application prospect.