Coagulative removal of polystyrene microplastics from aqueous matrices using FeCl3-chitosan system: Experimental and artificial neural network modeling

Effluent from sewage treatment plants (STPs) is a significant source of microplastics (MPs) re-entry into the environment. Coagulation-flocculation-sedimentation (CFS) process as an initial tertiary treatment step requires investigation for coagulative MPs removal from secondary-treated sewage effluents. In this study, experiments were conducted on synthetic water containing 25 mg/L polystyrene (PS) MPs using varying dosages of FeCl3 (1-10 mg/L) and chitosan (0.25-9 mg/L) to assess the effect of process parameters, such as pH (4-8), stirring speed (0-200 rpm), and settling time (10-40 min). Results revealed that ∼89.3% and 21.4% of PS removal were achieved by FeCl3 and chitosan, respectively. Further, their combination resulted in a maximum of 99.8% removal at favorable conditions: FeCl3: 2 mg/L, chitosan: 7 mg/L, pH: 6.3, stirring speed: 100 rpm, and settling time: 30 min, with a statistically significant (p < 0.05) effect. Artificial neural network (ANN) validated the experimental results with RMSE = 1.0643 and R2 = 0.9997. Charge neutralization, confirmed by zeta potential, and adsorption, ascertained by field-emission scanning electron microscope (FESEM) and Fourier-transform infrared spectroscopy (FTIR), were primary mechanisms for efficient PS removal. For practical considerations, the application of the FeCl3-chitosan system on the effluents from moving bed biofilm reactor (MBBR) and sequencing batch reactor (SBR)-based STPs, spiked with PS microbeads, showed > 98% removal at favorable conditions.

End-functionalized polymers by controlled/living radical polymerizations: synthesis and applications

This review focuses on end-functionalized polymers synthesized by controlled/living radical polymerizations and the applications in fields including bioconjugate formation, surface modification, topology construction, and self-assembly.

Tunable Mechanical, Electrical, and Thermal Properties of Polymer Nanocomposites through GMA Bridging at Interface

Polymer nanocomposites (PNCs) have become an exciting field of current research and have attracted a huge interest among both academia and industry during the last few decades. However, the multifunctional single-nanocomposite film exhibiting the combination of desired structure and properties still remains a big challenge. Herein, we report a novel strategy to address these problems by using versatile polymer glycidyl methacrylate (GMA) as a bridging medium between the filler and the polymer matrix, resulting in high density of interfaces as well as strong interactions, which lead to generation of tunable thermal, mechanical, and electrical properties in the materials. The nanocomposites prepared by GMA bridging exhibit the remarkable combination of thermal (T _d = 342.2 °C, T _g = 150.1 °C ), mechanical (E = 7.6 Gpa and H = 0.45 Gpa ) and electrical (σ = 3.15 × 10^-5 S/cm) properties. Hence, the conjugation approaches related to GMA bridging facilitate a new paradigm for producing multifunctional polymer nanocomposites having a unique combination of multifunctional properties, which can be potentially used in next-generation polymer-based advanced functional devices.

Swift Heavy Ion Irradiation as a Tool for Homogeneous Dispersion of Nanographite Platelets within the Polymer Matrices: Toward Tailoring the Properties of PEDOT:PSS/Nanographite Nanocomposites

Performance of the polymer nanocomposites is dependent to a great extent on efficient and homogeneous dispersion of nanoparticles in polymeric matrices. The dispersion of nanographite platelets (NGPs) in polymer matrix is a great challenge because of the inherent inert nature of the NGPs, poor wettability toward polymer matrices, and easy agglomeration due to van der Waals interactions. In the present study, attempts have been made to use a new approach involving the irradiation of polymer nanocomposites through swift heavy ion (SHI) to homogeneously disperse the NGPs within the polymer matrices. Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (

PEDOT

PSS)/nanographite nanocomposite (NC) films prepared by the solution blending method were irradiated with SHI (Ni ion beam, 80 MeV) at a fluence range of 1 × 10(10) to 1 × 10(12) ions/cm(2). XRD studies revealed that ion irradiation results in delamination and better dispersion of NGPs in the irradiated nanocomposite films compared to unirradiated films, which is also depicted through SEM, AFM, TEM, and Raman studies. In the irradiated polymer nanocomposite films, the conformation of PEDOT chains changes from coiled to extended coiled structure, which, along with homogeneously dispersed NGPs in irradiated NCs, shows an excellent synergistic effect facilitating charge transport. The remarkable improvement in conductivity from 1.9 × 10(-2) in unirradiated NCs to 0.45 S/cm in irradiated NCs is observed with marked improvement in sensing the response toward nitroaromatic vapors at room temperature. The temperature induced conductivity studies have been carried out for

PEDOT

PSS/nanographite NCs to comprehend the charge transport mechanism in NC films using the 3D Mott variable range hopping model also. The study reveals SHI as a novel method, addressing the challenge associated with the dispersion of NGPs within the polymer matrix for their enhanced performance toward various applications.

Strategy to synthesise nano-engineered polymer nanocomposite with a mechanically strong interface: a highly flexible ammonia gas sensor

The work reported herein describes a facile strategy for synthesize of a highly flexible and free standing novel polymethyl methacrylate/nanographite platelets nanocomposite (P-NC) film through click chemistry.