Zhipeng Liao

Heavy metal ion contamination in aquatic systems presents substantial environmental and public health challenges, demanding innovative remediation solutions. This study reports the synthesis of phosphorylated cellulose (PC) monoliths via thermally induced phase separation (TIPS) as a sustainable solution for heavy metal removal. Through systematic optimization of phosphorylation degree (ranging from 16.3% to 49.5%) and pore architecture, we developed materials with exceptional adsorption capacity and flow characteristics. Comprehensive characterization (SEM, FTIR, and elemental analysis) confirmed the successful incorporation of the phosphate group while revealing tunable three-dimensional porous structures controlled by cellulose acetate concentration (80–120 mg mL⁻¹) and phosphorylation parameters. Optimal Cu²⁺ adsorption occurs at 43.9% phosphorylation, coupled with stable permeability, under continuous flow conditions. The monolith effectively removes heavy metal ions (e.g., Cu²⁺, Ni²⁺, Cd²⁺) across a wide pH range, driven by electrostatic and hard-soft acid-base interactions. Additionally, the material maintains an absorption capacity of over 90% after multiple regeneration cycles. These findings highlight the potential of PC monoliths as cost-effective, scalable, and environmentally friendly adsorbents for heavy metal ion removal in water treatment applications.

The structure and composition of nanofillers have a significant influence on polyamide nanofiltration (NF) membranes. In this work, an asymmetric organic nanobowl containing a concave cavity was synthesized and incorporated into a polyamide layer to prepare thin film nanocomposite (TFN) membranes via an interfacial polymerization process. Benefiting from the hydrophilicity, hollow cavity and charge property of the compatible organic nanobowls, the separation performance of the developed TFN membrane was significantly improved. The corresponding water fluxes increased to 119.44 ± 5.56, 141.82 ± 3.24 and 130.27 ± 2.05 L/(m²·h) toward Na₂SO₄, MgCl₂ and NaCl solutions, respectively, with higher rejections, compared with the control thin film composite (TFC) and commercial (CM) membranes. Besides this, the modified TFN membrane presented a satisfying purification performance toward tap water, municipal effluent and heavy metal wastewater. More importantly, a better antifouling property of the TFN membrane than TFC and CM membranes was achieved with the assistance of organic nanobowls. These results indicate that the separation performance of the TFN membrane can be elevated by the incorporation of organic nanobowls.

This paper studies the averaging GMM estimator that combines a conservative GMM estimator based on valid moment conditions and an aggressive GMM estimator based on both valid and possibly misspecified moment conditions, where the weight is the sample analog of an infeasible optimal weight. We establish asymptotic theory on uniform approximation of the upper and lower bounds of the finite‐sample truncated risk difference between any two estimators, which is used to compare the averaging GMM estimator and the conservative GMM estimator. Under some sufficient conditions, we show that the asymptotic lower bound of the truncated risk difference between the averaging estimator and the conservative estimator is strictly less than zero, while the asymptotic upper bound is zero uniformly over any degree of misspecification. The results apply to quadratic loss functions. This uniform asymptotic dominance is established in non‐Gaussian semiparametric nonlinear models.