Chunxia Zhou

Mussel-inspired synthesis of polydopamine-functionalized calcium carbonate as reusable adsorbents for heavy metal ions

A new high-efficiency adsorbent (PDA-CaCO3) is fabricated via simple thermal calcination of ostracean shells and chemical modification with dopamine. The adsorption capacity for Pb(II) and Cd(II) was 336.32 and 175.48 mg g−1, respectively. Importantly, it can be easily regenerated by low-cost reagents, and exhibited a high adsorption capacity after multiple adsorption–desorption cycles.

Novel low temperature (<37 °C) chitosan hydrogel fabrication under the synergistic effect of graphene oxide

A novel low temperature chitosan hydrogel (<37 °C) was fabricated via a simple mixing method under the synergistic effect of graphene oxide. The effect of the concentration of chitosan, β-glycerophosphate and graphene oxide on the gelation temperature and time of the chitosan hydrogel was studied. It can begin to form a gel at under 33 °C after adding 0.3 wt% graphene oxide, which is 6 °C lower than the temperature required for a chitosan hydrogel without graphene oxide. In addition, the gelation time is shortened to 9 min under the synergistic effect of graphene oxide. The controlled release of drugs from this hydrogel is also improved compared with that from traditional chitosan hydrogels. This novel low temperature hydrogel is expected to be applied in the field of hydrogel medical coatings.

Electrochemical Determination of Nitrite by Au Nanoparticle/Graphene-Chitosan Modified Electrode

A highly sensitive nitrite (NO2−) electrochemical sensor is fabricated using glassy carbon electrode modified with Au nanoparticle and grapheme oxide. Briefly, this electrochemical sensor was prepared by drop-coating graphene oxide-chitosan mixed film on the surface of the electrode and then electrodepositing a layer of Au nanoparticle using cyclic voltammetry. The electrochemical behavior of NO2− on the sensor was investigated by cyclic voltammetry and amperometric i-t curve. The results showed that the sensor exhibited better electrocatalytic activity for NO2− in 0.1 mol/L phosphate buffer solution (PBS) (pH 5.0). The oxidation peak current was positively correlated with NO2− concentration in the ranges of 0.9 µM to 18.9 µM. The detection limit was estimated to be 0.3 µM. In addition, the interference of some common ions (e.g., NO3−, CO32−, SO42−, Cl−, Ca2+ and Mg2+) and oxidizable compound including sodium sulfite and ascorbic acid in the detection of nitrite was also studied. The results show that this sensor is more sensitive and selective to NO2−. Therefore, this electrochemical sensor provided an effective tool for the detection of NO2−.