Ji-Lai Gong

Removal of cationic dyes from aqueous solution using magnetic multi-wall carbon nanotube nanocomposite as adsorbent.

A magnetic multi-wall carbon nanotube (MMWCNT) nanocomposite was synthesized and was used as an adsorbent for removal of cationic dyes from aqueous solutions. The MMWCNT nanocomposite was composed of commercial multi-wall carbon nanotubes and iron oxide nanoparticles. The properties of this magnetic adsorbent were characterized by scanning electron microscopy, X-ray diffraction and BET surface area measurements. Adsorption characteristics of the MMWCNT nanocomposite adsorbent were examined using methylene blue, neutral red and brilliant cresyl blue as adsorbates. Experiments were carried out to investigate adsorption kinetics, adsorption capacity of the adsorbent and the effect of adsorption dosage and solution pH values on the removal of cationic dyes. Kinetic data were well fitted by a pseudo second-order model. Freundlich model was used to study the adsorption isotherms. The prepared MMWCNT adsorbent displayed the main advantage of separation convenience compared to the present adsorption treatment.

Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials: a review.

Nowadays nanomaterials have been widely used to remove heavy metals from water/wastewater due to their large surface area and high reactivity. Humic acid (HA) and fulvic acid (FA) exist ubiquitously in aquatic environments and have a variety of functional groups which allow them to complex with metal ions and interact with nanomaterials. These interactions can not only alter the environmental behavior of nanomaterials, but also influence the removal and transportation of heavy metals by nanomaterials. Thus, the interactions and the underlying mechanisms involved warrant specific investigations. This review outlined the effects of HA/FA on the removal of heavy metals from aqueous solutions by various nanomaterials, mainly including carbon-based nanomaterials, iron-based nanomaterials and photocatalytic nanomaterials. Moreover, mechanisms involved in the interactions were discussed and potential environmental implications of HA/FA to nanomaterials and heavy metals were evaluated.

Shellac-coated iron oxide nanoparticles for removal of cadmium(II) ions from aqueous solution.

This study describes a new effective adsorbent for cadmium removal from aqueous solution synthesized by coating a shellac layer, a natural biodegradable and renewable resin with abundant hydroxyl and carboxylic groups, on the surface of iron oxide magnetic nanoparticles. Transmission Electron Microscopy (TEM) imaging showed shellac-coated magnetic nanoparticle (SCMN) adsorbents had a core-shell structure with a core of 20 nm and shell of 5 nm. Fourier Transform Infrared Spectroscopic analysis suggested the occurrence of reaction between carboxyl groups on the SCMN adsorbent surface and cadmium ions in aqueous solution. Kinetic data were well described by pseudo second-order model and adsorption isotherms were fitted with both Langmuir and Freundlich models with maximum adsorption capacity of 18.80 mg/g. SCMN adsorbents provided a favorable adsorption capacity under high salinity conditions, and cadmium could easily be desorbed using mild organic acid solutions at low concentration.

An electrochemical sensor for detection of laccase activities from Penicillium simplicissimum in compost based on carbon nanotubes modified glassy carbon electrode.

An electrochemical sensor for detection of the activity of laccase from Penicillium simplicissimum isolated from the composting has been developed. The sensor is based on glassy carbon electrode modified with multi-wall carbon nanotubes (CNTs). The introduction of CNTs into this system can greatly enhance the electrochemical signal in this assay more sensitively, selectively and rapidly than that in conventional spectrophotometric assays. It was found that the optimal pH value of the electrolyte was 5.6. The results showed a good linear correlation between the current and the concentration of laccase activities measured by spectrophotometry, where the current slope was measured by chronoamperometry with a coefficient of 0.9835. Therefore, this electrochemical sensor can be used for rapid detection of laccase activity from P. simplicissimum. Furthermore, it may be potentially used for rapid quantification of P. simplicissimum according to the relationship between the laccase activities and the biomass.

Impact of carbon nanotubes on the mobility of sulfonamide antibiotics in sediments in the Xiangjiang River

Manufactured in numerous factories, and contained in various consumer products, carbon nanotubes (CNTs) and sulfonamide antibiotics (SAs) may be released into the environment by many pathways. The sorption behavior of CNTs on SAs may increase the environmental and health risks when exposed to SAs–CNTs composites. In this study, we investigated the mobility of SAs in sediment columns in the presence/absence of CNTs. Three kinds of SAs (sulfamethoxazole, sulfapyridine, and sulfadiazine) and two kinds of CNTs (multi-walled carbon nanotubes, MWCNTs and single-walled carbon nanotubes, SWCNTs) in sediments from the Xiangjiang River were investigated in this study. The results showed that the SAs were of high mobility in sediment columns. However, CNTs with a concentration of 4.8 mg g−1 in the sediment could dramatically retain SAs, which might be due to the limited transport of CNTs and their high adsorption capacities of SAs. The percentage of SAs retention in sediment became higher when CNTs existed in the inflow, suggesting that a strong CNTs-associated SAs reaction might occur in the sediment. The findings in this study indicated that CNTs in the sediment environment or river system can reduce the mobility of SAs, which should be taken into account when evaluating the potential environmental risks of SAs and CNTs.