Novel Graphene Oxide–Confined Nanospace Directed Synthesis of Glucose-Based Porous Carbon Nanosheets with Enhanced Adsorption Performance

Glucose-based porous carbon nanosheets (GPCNS) were synthesized by an integrated graphene oxide–confined nanospace directed KOH-activated process and were applied as adsorbent for efficient removal of sulfamethazine (SMZ). The effects of GO dosage on the structure, specific surface area, and adsorption capacity of GPCNS-<i>x</i> were investigated. The highest SMZ uptake of 820.27 mg g^–1 (298 K) was achieved in glucose-based porous carbon nanosheets inherited from using 1% GO relative to glucose (GPCNS-1). Also, the adsorption isotherms, thermodynamics, and kinetics of SMZ onto GPCNS-1 were studied in detail. In addition, the effects of ionic strength and solution pH on the adsorption capacity of GPCNS-1 were also investigated, indicating good environmental tolerance of GPCNS-1. Furthermore, regeneration experiments showed that GPCNS-1 has good reproducibility and durability. We believe that these graphene oxide–confined nanospace directed KOH-activated process biomass-based carbon nanosheets are highly promising as absorbents in the field of environmental protection

Selective Adsorption of Methylparaben by Submicrosized Molecularly Imprinted Polymer: Batch and Dynamic Flow Mode Studies

Highly selective submicrosized molecularly imprinted polymer (SMIP_MP) for methylparaben (MP) was synthesized by molecular imprinting technique with a sol–gel process on silica submicroparticles. The prepared SMIP_MP was characterized by FT-IR, SEM, TG, and N₂ adsorption–desorption techniques. Compared with microsized methylparaben imprinted polymer (MMIP_MP) adsorbent, SMIP_MP adsorbent with small particle size and high specific surface area showed faster adsorption rate and stronger adsorption capacity for MP. The maximum static adsorption capacity for MP of SMIP_MP was 32.68 mg g^–1, and the adsorption equilibrium could be reached in 40 min. The SMIP_MP adsorbent could be used at least 5 times without significant loss in adsorption capacity. Compared with submicrosized nonimprinted polymer (SNIP), SMIP_MP indicated excellent recognition and binding affinity toward MP molecules, whose selectivity coefficients for MP relative to methyl salicylate (MS) and <i>p-</i>hydroxybenzoic acid (<i>p-</i>HB) were 5.664 and 6.129, respectively. The mechanism for static adsorption of MP onto SMIP_MP was found to follow Freundlich, Redlich-Peterson isotherm, and pseudo-second-order model. Thomas’ model was applied in the quantitative description and parametrization of the dynamic adsorption of MP to SMIP_MP and SNIP, which showed that the linear and nonlinear methods were both suitable to predict the breakthrough curves but the nonlinear method was better

Fabrication and Evaluation of Magnetic/Hollow Double-Shelled Imprinted Sorbents Formed by Pickering Emulsion Polymerization

Magnetic/hollow double-shelled imprinted polymers (MH-MIPs) were synthesized by Pickering emulsion polymerization. In this method, attapulgite (ATP) particles were used as stabilizers to establish a stable oil-in-water emulsion, and a few hydrophilic Fe₃O₄ nanoparticles were allowed to be magnetic separation carriers. The imprinting system was fabricated by radical polymerization in the presence of the functional and polymeric monomers in the oil phase. The results of characterization indicated that MH-MIPs exhibited magnetic sensitivity (<i>M</i>_s = 4.76 emu g^–1), thermal stability (especially below 200 °C), and hollow structure and were composed of exterior ATP shells and interior imprinted polymers shells. Then MH-MIPs were evaluated as sorbents for the selective binding of λ-cyhalothrin as a result of their magnetism, enhanced mechanical strength, hydrophilic surface, and recognition ability. The kinetic properties of MH-MIPs were well described by the pseudo-second-order equation, indicating that the chemical process could be the rate-limiting step in the adsorption process for λ-cyhalothrin. The equilibrium adsorption capacity of MH-MIPs was 60.06 μmol g^–1 at 25 °C, and the Langmuir isotherm model gave a better fit to the experimental data, indicating the monolayer molecular adsorption for λ-cyhalothrin. The selective recognition experiments also demonstrated the high affinity and selectivity of MH-MIIPs toward λ-cyhalothrin over fenvalerate and diethyl phthalate

A Hierarchical Porous Bowl-like PLA@MSNs-COOH Composite for pH-Dominated Long-Term Controlled Release of Doxorubicin and Integrated Nanoparticle for Potential Second Treatment

We chemically integrated mesoporous silica nanoparticles (MSNs) and macroporous bowl-like polylactic acid (pBPLA) matrix, for noninvasive electrostatic loading and long-term controlled doxorubicin (DOX) release, to prepare a hierarchical porous bowl-like pBPLA@MSNs-COOH composite with a nonspherical and hierarchical porous structure. Strong electrostatic interaction with DOX rendered excellent encapsulation efficiency (up to 90.14%) to the composite. DOX release showed pH-dominated drug release kinetics; thus, maintaining a weak acidic pH (e.g., 5.0) triggered sustained release, suggesting the composite’s great potential for long-term therapeutic approaches. In-vitro cell viability assays further confirmed that the composite was biocompatible and that the loaded drugs were pharmacologically active, exhibiting dosage-dependent cytotoxicity. Additionally, a wound-healing assay revealed the composite’s intrinsic ability to inhibit cell migration. Moreover, pH- and time-dependent leaching of the integrated MSNs due to pBPLA matrix degradation allow us to infer that the leached (and drug loaded) MSNs may be engulfed by cancer cells contributing to a second wave of DOX-mediated cytotoxicity following pH-triggered DOX release