Chitosan-modified magnetic carbon nanomaterials with high efficiency, controlled motility, and reusability-for removal of chromium ions from real wastewater.

Hexavalent chromium Cr(VI) is one of the most hazardous oxygen-containing anions to human health and the environment. Adsorption is considered to be an effective method for the removal of Cr(VI) from aqueous solutions. Based on an environmental perspective, we used renewable biomass cellulose as carbon source and chitosan as functional material to synthesize chitosan-coated magnetic carbon (MC@CS) material. The synthesized chitosan magnetic carbons were uniform in diameter (~ 20 nm) and contain a large number of abundant hydroxyl and amino functional groups on the surface, meanwhile owning excellent magnetic separation properties. The MC@CS exhibited high adsorption capacity (83.40 mg/g) at pH 3 and excellent cycling regeneration ability when applied to Cr(VI) removal in water, removal rate of Cr(VI) (10 mg/L) was still over 70% after 10 cycles. FT-IR and XPS spectra showed that electrostatic interaction and reduction with Cr(VI) are the main mechanisms of Cr(VI) removal by MC@CS nanomaterial. This work provides an environment-friendly adsorption material that could be reused for the removal of Cr(VI) in multiple cycles.

[Diagnosis and treatment of giant cell tumor of tendinous sheath in wrist].

OBJECTIVE: To investigate diagnostic methods and surgical effect for the treatment of giant cell tumor of tendinous sheath in wrist. METHODS: From September 2002 to October 2009, 8 patients with preoperative diagnosis as giant cell tumor of tendinous sheath based on MRI were treated surgically. There were 5 males and 3 females, ranging in age from 16 to 65 years, with an average of 41 years. The disease course ranged from 10 to 72 months with an average of 31 months. RESULTS: The diagnosis of all the patients was confirmed as giant cell tumor of tendinous sheath by postoperative pathology. All the patients were followed up, and the during ranged from 5 to 48 months (averaged, 34.2 months). One patient recurred and 3 patients got obvious relief of symptoms of median nerve injury. All the patients had significant improvement in wrist function after surgery. CONCLUSION: Preoperative MRI is helpful for differential diagnosis of giant cell tumor of tendinous sheath. Thorough removal of tumor is very important in prevention of recurrence.