UV–VIS photo catalytic degradation

UV–VIS photo catalytic degradation of nitro benzene from water using
heavy metal doped titania.

Variations in the concentrations of major particulate heavy metals (PHMs) (Mn, Pb, Zn, V, Cr, and Ni) and fluxes
into the sea during the water–sediment regulation scheme (WSRS) in the Huanghe (Yellow River) were examined
based on observational and measured data during June and July of 2009. Two stages of variations in the concentrations
of PHMs were observed in the WSRS with lower values in the early stage and higher values in the late
stage. The early stage corresponded to a high water discharge with coarser sediment that was largely scored from
the riverbed, and the late stage corresponded to a low water discharge with much finer sediment that was
released from the Xiaolangdi reservoir. The significant increase in PHM concentrations by 2–4 fold from the
early to the late stage largely resulted from a decrease in the suspended-sediment grain size and an increase in
the quantity of anthropogenic pollutants caused by changes in the sediment sources from riverbed in the
lower reaches to the Xiaolangdi reservoir during the WSRS. The concentrations of PHMs, particularly in the
late stage of theWSRS, were approximately two times as high as those during the pre-WSRS period as the anthropogenic
pollutants have been increasing in recent years. More than 57% of the annual quantity of PHMs was
transported to the sea during the WSRS, and over 34% of that from the Xiaolangdi reservoir was delivered to
the sea during the late stage of the WSRS over a period of approximately 4–5 days. This large quantity of
heavy metals, with a high proportion of labile components because of the increasing contribution of anthropogenic
pollutants, emptied into the sea over a short period and may thus drastically alter the eco-environment
in the river mouth and its adjacent seas.