Inspired by the mastoid structure of the lotus leaf and the robust layered structure of the nacre, a novel nacrelike graphene oxide−calcium carbonate (GO−CaCO 3 ) hybrid mesh with superhydrophilic and underwater superoleophobic property was prepared for the first time, via a facile, economical, and environmentally friendly layer-by-layer (LBL) self-assembly method using commercially available stainless steel mesh (SSM) as a ready-made mask. Interestingly, GO nanosheets played a threefold role, regulating the growth of CaCO 3 nanocrystals between the GO interlamination for constructing a "brick-and-mortar" structure, improving the interface stability via coordination assembly onto SSM, and creating strong hydration derived from rich oxygencontaining functional groups. The surface hydrophilicity and hierarchically micro/nanoscale structure of GO−CaCO 3 artificial pearls imbed on the SSM, contributing to outstanding superhydrophilicity and underwater superoleophobicity. The biomimetic hybrid mesh exhibited a strong mechanical property with a Young's modulus of 25.4 ± 2.6 GPa. The optimized hybrid mesh showed a high separation efficiency of more than 99% toward a series of oil/water mixtures with high flux. The low oil-adhesion force, high fatigueresistance, chemical stability (acid/alkali/salt resistance), and excellent recycling performance enlighten the great prospects of GObased nacrelike material for application in oily wastewater treatment.

Here, the magnetic hierarchical porous carbon (MHPC) with micromesopores was first prepared using ethylenediaminetetraacetic acid tripotassium (EDTA-3K) and iron nitrate by simultaneous magnetization/activation method. The optimal product was MHPC-20 with a high graphitization, which possessed a large S BET (1688 m2 g–1) and saturation magnetization (3.679 emu g–1). As expected, MHPC-20 had a very high maximum adsorption capacity (534.2 mg g–1) toward chloramphenicol (CAP) from water solution at 298 K with a positive correlation between S BET and adsorption amount. Additionally, MHPC-20 had a fast adsorption kinetic, only 250 min, and isothermal and kinetics data were well fitted by Langmuir and pseudo-second-order kinetic models, respectively. Moreover, the effect of ion strength, solution pH, and humic acid on CAP adsorption onto MHPC-20 were investigated, indicating a better stability. Besides, MHPC-20 showed good reusability and excellent magnetic separation performance, which implied MHPC-20 as a candidate could be applied in various complex wastewater environments.

In the present study, a Cr(III)-imprinted polymer (Cr(III)-IIP) was prepared by an easy one-step sol-gel reaction with a surface imprinting technique on the support of silica mesoporous material. A new SPE method for the speciation, separation, preconcentration, and determination of Cr(III) and Cr(VI) by inductively coupled plasma atomic emission spectrometry and UV on the mesoporous-imprinted polymer adsorbent was developed. The structure of the imprinted polymer was characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy, and nitrogen adsorption-desorption isotherms. The adsorption kinetics, thermodynamics behavior, and recognition ability toward Cr(III) on Cr(III)-IIP and nonimprinted polymer were compared. The results showed that Cr(III)-IIP had higher selectivity and nearly a two times larger Langmuir adsorption capacity (38.50 mg/g) than that of NIP. The proposed method has been successfully applied in the determination and speciation of chromium in natural water samples with satisfactory results.

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