It would be of significance to design a green composite for efficient removal of contaminants. Herein, we fabricated a facile and environmentally friendly composite via direct assembly of surface passivated carbon dots with abundant oxygen-containing functional groups on the surface of the positively charged layered double hydroxide (LDH). The resulting LDH-carbon dot composites were characterized by X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and N2 adsorption-desorption technique. The adsorption performances of the resulting LDH-carbon dot composites were evaluated for the removal of anionic methyl blue dye. Taking advantage of the combined benefits of LDH and carbon dots, the as-prepared composites exhibited high uptake capability of methyl blue (185 mg/g). The adsorption behavior of this new adsorbent fitted well with Langmuir isotherm and the pseudo-second-order kinetic model. The reasons for the excellent adsorption capacity of methyl blue on the surface of the LDH-carbon dot hybrid were further discussed. A probable mechanism was speculated to involve the cooperative contributions of hydrogen bonding between methyl blue and carbon dots and electrostatic attraction between methyl blue and LDH, in the adsorption process. This work is anticipated to open up new possibilities in fabricating LDH-carbon dot materials in dealing with anionic dye pollutants.

The development of a new heterogeneous Fenton-like catalyst is highly desired. Herein, we reported a simple and efficient method for the preparation of colloidal nanocomposites consisting of carbon dots and dodecylbenzenesulfonate (DBS)-layered double hydroxides (LDHs). The resulting nanocatalyst can function as an effective heterogeneous Fenton-like catalyst for the decomposition of acidified H 2 O 2 to generate abundant hydroxyl radicals (•OH). With the aid of chemiluminescence (CL) technique, electron spin resonance (ESR) measurements and ion chromatography (IC) separation technique, we demonstrated that the unique structural configuration of the carbon dot-DBS-LDH nanocomposites was responsible for the highly efficient catalytic activities toward H 2 O 2 decomposition. The fabricated material introduced a novel family of Fenton-like nanocatalysts with environmental friendliness, cost effectivity, and superior efficiency for the decomposition of H 2 O 2 to •OH radicals. Such heterogeneous Fenton-like catalyst could realize the degradation of DBS without any external energy input, showing a promising application for the oxidative degradation of organic contaminants in wastewater treatment applications.

In this work, carbon nanospheres (CNSs) were prepared with glucose through a hydrothermal synthesis method. Subsequently, a cetyltrimethylammonium bromide (CTAB) bilayer was used to modify the surface of the as-prepared CNSs (denoted as CTAB-CNSs). Interestingly, it was found that CTAB-CNSs could significantly amplify chemiluminescence (CL) emissions from some reactive oxygen species systems, including the Co(II)-H 2 O 2 -OH À system, ClO À system and ONOO À system. The CL intensity was proportional to the concentration of H 2 O 2 in the Co(II)-H 2 O 2 -OH À system in a linear range of 5-1000 mM with a limit of detection of 2.6 mM (S/N ¼ 3). The enhancement mechanism of CTAB-CNSamplified CL from the Co(II)-H 2 O 2 -OH À system was investigated using the fluorescence spectra, CL spectrum, scavengers of reactive oxygen species, and UV-vis absorption spectra. The results indicated that the CTAB bilayer on the surface of CNSs could form a particular micelle microenvironment, facilitating the reaction between reactive intermediates and CNSs. Finally, this method has been successfully used to detect H 2 O 2 in river water and lake water samples, and the recoveries were from 96 to 110%. The relative standard deviation (RSD) for nine repeated measurements was less than 5%. 010 64411957; Tel: +86 010 64411957 † Electronic supplementary information (ESI) available: Effect of the preparation time of CNSs on the CL intensity; TEM image of CNSs; FTIR spectrum of the as-prepared CTAB-CNSs and zeta potential measurements of CTAB-CNSs, CTAB and CNSs; effect of NaOH on the CL intensity; effect of CNSs modied with CTAB, TTAB, SDS and Triton X-100 on CL intensity; CL intensity of the ClO À -H 2 O 2 system and the ONOO À system in the presence of CTAB-CNSs; absorbance spectra of NBT in the absence or presence of the CTAB-CNS-Co(II)-H 2 O 2 -OH À system; tolerance limit of various coexisting substances on the determination of 50 mM H 2 O 2 ; effects of radical scavengers on the CTAB-CNS-Co(II)-H 2 O 2 -OH À system. See