Lead adsorption behaviours on nanoscale zero valent irons (nZVI) coupled with rice husk MCM-41

The aims of this work were to investigate the characteristics of nanoscale zero valent irons (nZVI) coupled with mesoporous materials (RH-MCM-41) adsorbent and to study the removal mechanisms of Pb (II) from synthetical solutions using full pictorial design batch experiments. Synthetic nZVI coupled with RH MCM-41 as Pb (II) adsorbent were characterized by XRD, TEM, BET and XANES. The results of XANES analyses confirmed the ability of RH-MCM-41 to prevent oxidations of Fe0 to Fe2+ and Fe3+. XANES results also verified the oxidation states of Pb (II). The solution pH was the most significant positive effect in controlling Pb (II) adsorption. The equilibrium and kinetic adsorption isotherms well fitted with the Langmuir isotherm. The pseudo-second order kinetic adsorption indicated that the adsorption process is the rate limiting step for Pb (II) removal. Furthermore, Langmuir-Hinshelwood confirmed the obvious Pb (II) adsorption at the active site of adsorbents. The reduction rate constant (kr = 5,000 mg/L.min) was higher than the adsorption rate constant (Kad = 0.0002 L/mg). Regarding the research results, four pathways including: reduction process, adsorption on FeOOH, adsorption on RH-MCM-41 and complex reaction between Fe and Pb ions were suggested for Pb (II) removal by nZVI coupled with RH-MCM-41

Barium Promotes Anchorage-Independent Growth and Invasion of Human HaCaT Keratinocytes via Activation of c-SRC Kinase

Explosive increases in skin cancers have been reported in more than 36 million patients with arsenicosis caused by drinking arsenic-polluted well water. This study and previous studies showed high levels of barium as well as arsenic in the well water. However, there have been no reports showing a correlation between barium and cancer. In this study, we examined whether barium (BaCl2) may independently have cancer-related effects on human precancerous keratinocytes (HaCaT). Barium (5–50 µM) biologically promoted anchorage-independent growth and invasion of HaCaT cells in vitro. Barium (5 µM) biochemically enhanced activities of c-SRC, FAK, ERK and MT1-MMP molecules, which regulate anchorage-independent growth and/or invasion. A SRC kinase specific inhibitor, protein phosphatase 2 (PP2), blocked barium-mediated promotion of anchorage-independent growth and invasion with decreased c-SRC kinase activity. Barium (2.5–5 µM) also promoted anchorage-independent growth and invasion of fibroblasts (NIH3T3) and immortalized nontumorigenic melanocytes (melan-a), but not transformed cutaneous squamous cell carcinoma (HSC5 and A431) and malignant melanoma (Mel-ret) cells, with activation of c-SRC kinase. Taken together, our biological and biochemical findings newly suggest that the levels of barium shown in drinking well water independently has the cancer-promoting effects on precancerous keratinocytes, fibroblast and melanocytes in vitro