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Chelating groups are successfully linked to graphene oxide (GO) surfaces through a silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane) and hydroxyl groups on GO surface. EDTA-GO was found to be an ideal adsorbent for Pb(II) removal with a higher adsorption capacity. EDTA-modification enhances the adsorption capacity of GO because of the chelating ability of ethylene diamine triacetic acid. This study investigates the adsorption and desorption behaviors of heavy metal cations and the effects of solution conditions such as pH on Pb(II) removal. The adsorption capacity for Pb(II) removal was found to be 479 ± 46) mg/g at pH 6.8, and the adsorption process was completed within 20 min. The Langmuir adsorption model agrees well with the experimental data. The experimental results suggest that EDTA-GO can be reused after washed with HCl, suggesting potential applications in the environmental cleanup.

We provide a wet chemical approach for organizing randomly tangled single-walled carbon nanotubes (SWCNTs) on gold surfaces. The as-grown nanotubes were first chemically cut into short pipes and thiol-derivatized at the open ends. The ordered assembly of SWCNTs was made by their spontaneous chemical adsorption to gold via Au−S bonds. Tapping mode atomic force microscopy (AFM) images clearly show that the nanotubes have been organized on gold, forming a self-assembled monolayer structure with a perpendicular orientation. The adsorption kinetics of the nanotubes was very slow in comparison to conventional alkanethiols. The adsorption rate varied inversely with tube length. The nanotubes tend to form bundles as the adsorption propagates, following a “nucleation adsorption mechanism”. This work demonstrates that “giant” carbon nanotubes can be assembled on Au surfaces using wet chemistry similar to that exploited for “small” organic self-assembling species. We believe that assembled nanotube arrays will provide wide possibilities for applications.

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Gelatin, a renewable animal derivative composed of various proteins, was used as a precursor for nitrogen-doped porous carbon with high surface areas for supercapacitors for the first time. The preparation procedure is very simple, including the carbonization of gelatin under inert atmosphere, followed by NaOH activation of the carbonized char at 600 C for 1 h. The porosity and surface chemistry of the carbon depend strongly on the weight ratio of NaOH/char, with the specific surface area and nitrogen content varying between 323 and 3012 m 2 g À1 and between 0.88 and 9.26 at%, respectively. The unique microstructure and nitrogen functionalities enable the carbon to exhibit a high capacitance of up to 385 F g À1 in 6 mol L À1 KOH aqueous electrolytes, attributed to the cocontribution of double layer capacitance and pseudo-capacitance. It also shows excellent rate capability (235 F g À1 remained at 50 A g À1 ) and cycle durability, making it a promising electrode material for supercapacitors.