Some researches on heavy metals treatment and disposal methods have been reported, the studies related to the single heavy metal toxicity are developed, but the relatively on toxicity of multi-compounds heavy metals and their mixture have been poorly discussed. This article describes the levels of single heavy metals, compares the strengths and weaknesses of diferent test methods, emphasizes on the characteristics of joint toxicity with mixture. The analysis results discover that the combined toxicity of heavy metals vary with different mixtures combinations, test target, methods and some predictive models were adopted to determine the dose-effect relationship. which propose the development direction of heavy metals toxicity, provide theoretical support for the establishment of environmental monitoring and evaluation methods system.
Static adsorption of Sb (III) on a porous biomorph-genetic composite of Fe2O3/Fe3O4/C (PBGC-Fe/C-B) was studied. The results showed that the kinetic curve of Sb (III) adsorption by PBGC-Fe/C-B had same change trend under initial concentration of 5, 10 and 50 mg/L. The fitting and regression analysis of four kinds of kinetic model indicated that, the adsorption kinetics of Sb (III) by the PBGC-Fe/C-B well follow the pseudo-second-order model (R2>0.9999). At different reaction temperature (25 °C, 35 °C and 45 °C), the adsorption capacity of Sb (III) by PBGC-Fe/C-B both increased with increasing the solution equilibrium concentration. While it showed a declined tendency with temperature increased. The Langmuir isotherm model (R2>0.98) and the Freundlich isotherm model (R2>0.95) had both better fitted with the equilibrium data.
The Dissolution of Synthetic Pyromorphite was Studied at 25°C in a Series of Batch Experiments. in Addition, the Aqueous Concentrations from the Batch Dissolution were Used to Calculate the Solubility Product and Free Energy of Formation of Pyromorphite. the Results of the Fourier Transform Infrared Spectroscopy Analyses Indicated that the Synthetic, Microcrystalline Pyromorphite with Apatite Structure Used in the Experiments has Not Changed after Dissolution. the Mean KspValue was Calculated for Pb5(PO4)3Cl of 10-78.31 at 25°C; the Free Energy of Formation ΔGf0[Pb5(PO4)3Cl] was-3756.82kJ/mol.
Adsorption of ammonia nitrogen from aqueous solution onto the bagasse adsorbent has been investigated to evaluate the effects of Adsorbent dose, initial NH4+-N concentration, and pH on the removal systematically. With increasing initial concentration, the amount of ammonia nitrogen sorbed onto the adsorbent increased until it gradually decreased due to the initial concentration exceed 50 mg·L-1, and the maximum adsorption capacity was observed for the sample to be 1.31 mg·g-1 at the initial concentration of 30 mg·L-1, and the corresponding removal rates decreased from 94.01 to 3.89%, with increase in initial concentration from 5 to 100 mg·L-1. Adsorption capacities decreased from 6.04 to 0.49 mg·g-1 with increasing adsorbent dose from 0.1 to 1.5g. What’s more, under alkaline condition, the removal efficiency of ammonia nitrogen from aqueous solution onto the samples were superior to that under acidity and neutrality condition.
Compared with the treatment of heavy metal waste water by bamboo charcoal and modified bamboo charcoal. The mainly types and methods of modified bamboo charcoal adsorption of pollution water is introduced. some important factors that effecting the bamboo charcoal and modified bamboo charcoal adsorption of heavy metal pollution were described in detail, summarizes the desorption method of the specific adsorbent and adsorption mechanism.
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