Zhaoqi Zhu

Superhydrophobic Activated Carbon‐Coated Sponges for Separation and Absorption

Highly porous activated carbon with a large surface area and pore volume was synthesized by KOH activation using commercially available activated carbon as a precursor. By modification with polydimethylsiloxane (PDMS), highly porous activated carbon showed superhydrophobicity with a water contact angle of 163.6°. The changes in wettability of PDMS- treated highly porous activated carbon were attributed to the deposition of a low-surface-energy silicon coating onto activated carbon (confirmed by X-ray photoelectron spectroscopy), which had microporous characteristics (confirmed by XRD, SEM, and TEM analyses). Using an easy dip-coating method, superhydrophobic activated carbon-coated sponges were also fabricated; those exhibited excellent absorption selectivity for the removal of a wide range of organics and oils from water, and also recyclability, thus showing great potential as efficient absorbents for the large-scale removal of organic contaminants or oil spills from water.

Synthesis of conjugated microporous polymer nanotubes with large surface areas as absorbents for iodine and CO2 uptake

Conjugated microporous polymer nanotubes (CMPNs) with a surface area of up to 1368 m2 g−1 were synthesized by a simple one-step crosscoupling reaction and employed as a platform for investigation of CO2 and I2 adsorption. A high adsorption capacity of up to 208 wt% for reversible I2 capture was achieved.

Capture and Reversible Storage of Volatile Iodine by Novel Conjugated Microporous Polymers Containing Thiophene Units

Conjugated microporous polymers having thiophene building blocks (SCMPs), which originated from ethynylbenzene monomers with 2,3,5-tribromothiophene, were designedly synthesized through Pd(0)/CuI catalyzed Sonogashira-Hagihara cross-coupling polymerization. The morphologies, structure and physicochemical properties of the as-synthesized products were characterized through scanning electron microscope (SEM), thermogravimeter analysis (TGA), (13)C CP/MAS solid state NMR and Fourier transform infrared spectroscope (FTIR) spectra. Nitrogen sorption-desorption analysis shows that the as-synthesized SCMPs possesses a high specific surface area of 855 m(2) g(-1). Because of their abundant porosity, π-conjugated network structure, as well as electron-rich thiophene building units, the SCMPs show better adsorption ability for iodine and a high uptake value of 222 wt % was obtained, which can compete with those nanoporous materials such as silver-containing zeolite, metal-organic frameworks (MOFs) and conjugated microporous polymers (CMPs), etc. Our study might provide a new possibility for the design and synthesis of functional CMPs containing electron-rich building units for effective capture and reversible storage of volatile iodine to address environmental issues.

Preparation of poly(acrylic acid)–graphite oxide superabsorbent nanocomposites

Graphite oxide (GO) nanoplatelets with a thickness from 0.8 nm to 2 nm were prepared using a modified Hummers method. By employing GO nanoplatelets as nanofillers, poly(acrylic acid)–GO superabsorbent nanocomposites were synthesized by a facile solution polymerization of acrylic acid monomers using N,N′-methylenebisacrylamide as cross-linker and ammonium persulfate as initiator. The well-dispersed GO nanoplatelets in the polymer networks results in a significant improvement in absorbencies both in distilled water and saline solutions. With only a very low loading of GO in the superabsorbent nanocomposite, for example 0.073 wt%, its water absorbency reaches up to 508 g g−1, which is nearly as twice that of the poly(acrylic acid) (PAA) superabsorbent. The superabsorbent nanocomposite also exhibits a superior water-retention ability compared with the control under the same conditions. Our study may provide a new way for the development of novel, GO-based superabsorbent nanocomposites with improved absorbency and may find a variety of useful applications.

Three‐Dimensional Superwetting Mesh Film Based On Graphene Assembly for Liquid Transportation and Selective Absorption

Superwetting membranes or porous absorbent materials have recently attracted considerable interest from both commercial and academic communities due to their excellent performance for separation or selective absorption of organic compounds and oils from water, which shows great potential for addressing environmental issues. Herein, the first example of engineering a commercially available stainless-steel grid based on the assembly of graphene for the fabrication of superwetting mesh films (SMFs) is reported. An excellent surface wettability of the SMFs, which exhibit a unique adhesion force to liquids, is observed; this makes it possible to transfer small quantities of liquid samples to perform microsample analysis. A three-dimensional SMF shows unprecedented performance in the separation, transportation, and selective absorption of organic compounds or oils from water. The performance is considerably improved in comparison to traditional separation/absorption technologies and may useful for a wide range of applications such as purification, water treatment, or oil-spill cleanup.

Robust and all-inorganic absorbent based on natural clay nanocrystals with tunable surface wettability for separation and selective absorption

We have developed a simple method for fabrication of a robust, three-dimensional all-inorganic porous attapulgite (ATP) monolith based on natural clay nanocrystals using CaCO3 as a hard template. By a simple surface modification with polydimethylsiloxane (PDMS) by the chemical vapour deposition method, the resulting hydrophilic ATP monolith can be tuned to be superhydrophobic and superolephilic for selective absorption of oils or weak polarity organics from water. Also, the surface wettability of the PDMS-treated ATP monolith can be reversibly tailored from superhydrophobic to hydrophilic by simple thermal treatment, making it a multifunctional absorbent for absorption of oils, non-polar or polar organics, and metal ions from water only by simply tuning its surface wettability.

Conjugated microporous polymers/n-carboxylic acids composites as form-stable phase change materials for thermal energy storage

Conjugated microporous polymers (CMPs) with large BET surface areas were used as porous supporting materials to prepare form-stable phase change material (PCM) composites. Due to the unique superoleophilicity of CMPs, PCMs could be absorbed spontaneously into CMPs and can stay stable in the CMP samples without leakage even over their melting points. Results obtained from X-ray powder diffraction (XRD) show that the incorporation of CMPs decreases the crystal size of PCMs in the composites. The latent heat of CMP/PCM composites was measured ranging from 103.3 kJ kg−1 to 171.0 kJ kg−1. The resulting PCM composites show excellent recyclability and thermal stability after 300 melting and freezing cycles, and have great potential for renewable energy saving applications.

Innovative nanoporous carbons with ultrahigh uptakes for capture and reversible storage of CO2 and volatile iodine.

Porous carbons as solid-state adsorbents have recently attracted considerable interest in the areas of storage and capture of CO2 as well as the adsorption of radioactive matters. In this work, cigarette butts, one kind of common wastes referring to the filters, were utilized to prepare highly porous carbons by KOH activation in argon atmosphere. The resulting porous carbon shows a high specific surface area of up to 2751m2g-1 with abundant micropores. The resulting porous carbon exhibits excellent iodine uptake of 262wt% and high CO2 adsorption capacity of 6.0mmolg-1 at ambient pressure and 273K, which both are among the highest values reported to date. Given these excellent iodine uptake, CO2 adsorption capacity, ease of preparation as well as good physiochemical stability, the porous carbons derived from cigarette butts show great potential in the reversible adsorption of radioactive iodine and CO2.

Reduced graphene oxide-coated cottons for selective absorption of organic solvents and oils from water

Superwetting materials have attracted considerable interest both in academia and industry. In this work, the reduced graphene oxide (RGO)-coated cotton (GCC) was prepared by a facile and inexpensive dip-coating method. By modification with polydimethylsiloxane (PDMS), superhydrophobic and superoleophilic GCC was obtained, which shows a water contact angle of 152°. The PDMS-treated GCC exhibits selective absorption of organics and oils from water with an absorption capacity up to 11 to 25 times its weight. Also, the as-prepared product shows excellent stability and recyclability; both saturated absorption capacity and water CA value remain nearly unchanged after 9 cycles of use. Taking advantage of the excellent absorption selectivity, simple fabrication process, good stability and recyclability, this material may find a variety of applications such as in water treatment, purification, separation, oil spill cleanups and so on.

Innovative spongy attapulgite loaded with n-carboxylic acids as composite phase change materials for thermal energy storage

Spongy attapulgite (s-ATP), a novel nanoporous material with a three-dimensional porous network, was assembled from purified attapulgite micropowder (p-ATP) and used as a host material to prepare composite form-stable phase change materials (PCMs). The average pore diameter of the spongy ATP network was measured as 13.3 nm and the pore walls consist of thin layers constructed of ATP nanorod-like crystals. Due to the capillary forces of spongy ATP, n-carboxylic acids can be easily absorbed into ATP samples by the vacuum method. The effects of the three-dimensional network structure of the supporting material on the thermal properties of the composites were investigated. The thermal energy storage, thermal stability and durability of the composite PCMs were tested by differential scanning calorimetry and thermogravimetry. The PCM/spongy ATP composites had a high heat storage capacity between 72.57 and 82.36 J g−1, corresponding to a mass fraction of n-carboxylic acids between 36.60% and 37.71%. The PCM/spongy ATP composites exhibited excellent thermal stability and durability, and may have great potential for renewable energy storage applications.