Study on phase evolution and promoting the pozzolanic activity of electrolytic manganese residue during calcination.

Electrolytic manganese residue (EMR) is a harmful by-product in the electrolytic manganese industry. Calcination is an efficient method for disposing EMR. In this study, thermogravimetric-mass spectrometry (TG-MS) combined with X-ray diffraction (XRD) was used for analysing the thermal reactions and phase transitions during calcination. The pozzolanic activity of calcined EMR was determined by the potential hydraulicity test and strength activity index (SAI) test. The leaching characteristics of Mn were determined by TCLP test and BCR SE method. The results showed that MnSO4 was converted into stable MnO2 during calcination. Meanwhile, Mn-rich bustamite (Ca0.228Mn0.772SiO3) was converted into Ca(Mn, Ca)Si2O6. The gypsum was transformed into anhydrite and then decomposed into CaO and SO2. Additionally, the organic pollutants and ammonia were completely removed following calcination at 700 °C. The leaching concentration of Mn decreased from 819.9 mg L-1 to 339.6 mg L-1 following calcination at 1100 °C. The chemical forms of Mn were transformed from acid-soluble fraction to residual fraction. The pozzolanic activity tests indicated that EMR1100-Gy maintained a complete shape. The compressive strength of EMR1100-PO reached 33.83 MPa. Finally, the leaching concentrations of heavy metals met the standard limits. This study provides a better understanding for the treatment and utilization of EMR.

Toxicological Evaluation toward Refined Montmorillonite with Human Colon Associated Cells and Human Skin Associated Cells.

Montmorillonite has been refined to overcome uncertainties originating from different sources, which offers opportunities for addressing various health issues, e.g., cosmetics, wound dressings, and antidiarrheal medicines. Herein, three commercial montmorillonite samples were obtained from different sources and labeled M1, M2, and M3 for Ca-montmorillonite, magnesium-enriched Ca-montmorillonite, and silicon-enriched Na-montmorillonite, respectively. Commercial montmorillonite was refined via ultrasonic scission-differential centrifugation and labeled S, M, or L according to the particle sizes (small, medium, or large, respectively). The size distribution decreased from 2000 nm to 250 nm with increasing centrifugation rates from 3000 rpm to 12,000 rpm. Toxicological evaluations with human colon-associated cells and human skin-associated cells indicated that side effects were correlated with excess dosages and silica sand. These side effects were more obvious with human colon-associated cells. The microscopic interactions between micro/nanosized montmorillonite and human colon-associated cells or human skin-associated cells indicated that those interactions were correlated with the size distributions. The interactions of the M1 series with the human cells were attributed to size effects because montmorillonite with a broad size distribution was stored in the M1 series. The M2 series interactions with human cells did not seem to be correlated with size effects because large montmorillonite particles were retained after refining. The M3 series interactions with human cells were attributed to size effects because small montmorillonite particles were retained after refining. This illustrates that toxicological evaluations with refined montmorillonite must be performed in accordance with clinical medical practices.

Synthesis of cross-linked carboxyl poly(glycerol methacrylate) and its application for the controlled release of doxorubicin.

A series of polymers were synthesized by cross-linking carboxyl poly(glycerol methacrylate) (PGOHMA) using hexamethylene diisocyanate (HDI). The structures and molecular weight were characterized by ¹H NMR and gel permeation chromatography (GPC). Nanoparticles were then fabricated for encapsulation of doxorubicin hydrochloride (DOX). The encapsulation and release were affected by the chemical structure and degree of cross-linking of the polymers. The polymers were quite effective in the encapsulation of DOX, and exhibited pH-dependent drug release. Specifically, the stability of nanoparticles in neutral pH was significant enhanced and the release rate was enhanced at acidic pH after cross-linking, which could be potential useful as a controlled drug release carrier, especially for anti-cancer drug.