| A lot of chromium-containing waste water and waste were produced consequently with the application of metallic chromium in industry of chromate.Due to the unproper diposal of chromium-containing waste water and leaching, the possibility of the soluble hexavalent chromium entering the potable water was increased which enhaced the risk of drinking water safety.Aluminum salts flocculant was widely used in water pufirication field for its its high efficiency, low water area, low cost. In response to the worse water quality, large flocculant doses were used in water plant. Many researches showed that excessive intake of aluminum is harm ful to human body, thus controlling the concentration of residual aluminum in drinking water is of great significance.According to above issues, the PAN-based carbon fibers (PAN-ACF) and coal-based granular activated carbon (GAC)were used to removal trace amount of hexavalent chromium from micro-polluted water and residual aluminium removing from drinking water under neutral condition(pH6.8-7.6)Analysis technologies,such as SEM, BET, FT-IR, Boehm titration experiments were used to character the PAN-based carbon fibers(PAN-ACF)and coal-based granular activated carbon (GAC),data of microstructure, specific surface area, pore width distribution and surface oxygen contained functional groups were obtained. The PAN-ACF were modified by air thermal oxidation, nitrate impregnation and hydrogen peroxide impregnation, and then the adsorption capacity of modified PAN-ACF were studied.In order to study the residual aluminium removal ability of PAN-ACF, the data of tap water's quality of some water plant in Jinan in 2008 was collected, and the Dynamic Variations of residual aluminium was studied. The effect of residual aluminium removal by PAN-ACF and GAC were studied and discussed. PAN-ACF and GAC were used in simple household water purification equipments, and further discussed on the continuous removal ability of the total residual aluminum from tap water.The results showed that PAN-ACF and GAC have low total removal rates of trace Cr (VI) (<20%) in neutral conditions.Kinetic data showed that the pseudo first order kinetic model is suitable to describe the adsorption process of the two adsorbents.The adsorption rate and equilibrium adsorption capacity increased slightly with the initial concentration.Effect on adsorption of trace Cr (VI) by modified PAN-ACF suggested that the adsorption capacity is promoted by the enhancing of the specific surface area, the affect of surface acidic functional groups isn't the dominant factor.The results showed that, due to the addition of flocculant dosage, the residual Al concentration ranged from less than 5μg/L to 81μg/L,Al concentrations met the limit in GB5749-2006,but the peak concentration was still higher than some developed countries which have a aluminium limit concentration in drinking water(0.050mg/L);Concentrations of some anions are relatively high, but have little effect on the removal of aluminum, almost have no change in the concentration of its own;The trace aluminium was removed obviously by the PAN-ACF only by contacting 20s with a final concentration below 5μg/L.The water sample treated by GAC has a slightly higher Al concentration than the PAN-ACF treated samples,but also was close to the detection limit of 5μg/L.Compared with GAC,PAN-ACF has a better removal ability of the residual aluminum from tap water; saturated aluminum loading data of PAN-ACF showed that the adsorption sites in the surface of adsorbents quickly lost activity with the conduction of the adsorption, the removal of aluminum particles from tap water was dominated by retaining and settlement, the gaps between PAN-ACF filaments were similar to large holes in the surface of GAC,some other ions and some inorganic substances were adsorbed or retained on the same time of removing aluminum from tap water, the overall removal efficiency was better than GAC.
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