We studied the removal of cadmium and copper from industrial wastewaters by a microalloyed aluminium composite. The composite was highly efficient, resulting in water concentrations of cadmium and copper below the maximal allowed concentrations for drinking water. Moreover, our results show that the removal mechanism is mainly based on reduction and coprecipitation, since Cd and Cu were removed from the wastewater in reduced forms as metals and hydroxides.Selected article from the Regional Symposium on Chemistry and Environment, Krusevac, Serbia, June 2003, organised by Dr. Branimir Jovancicevic 相似文献
Agricultural practices can lead to copper accumulation in soils and at high concentration it can become toxic for plants.
One common toxic effect of copper on plants is a decrease of crop yield. Here, we studied 1) the crop yield of maize grown
on plots of a soil intentionally enriched with copper sulphate and 2) the possible relationship between the copper concentration
in chemical soil fractions and the maize crop yield. Anthropogenic copper is mainly bound to manganese oxides, to iron oxides
and to the organic matter. Maize (Zea maize L.) was grown on outdoor experimental plots. The crop yield was evaluated for three development stages: the 6–10 leaf stage,
the female flowering stage and the maturity stage, 2, 4 and 6 years after the soil copper enrichment. Strong crop yield reductions,
proving a toxic effect of copper on maize growth were noted 2 years after the copper input at the maturity stage and 4 years
after the copper input at the 6–10 leaf stage. Variations in maize crop yield are described with linear multiple regression
equations including the variable copper content in soil, and other variables when needed such as soil pH, soil organic carbon
level and the climatic variables, the precipitation rate and the ambient temperature. The crop yield study at the 6–10 leaf
stage and at the female flowering stage does not provide significant regression equations, while the crop yield study at the
maturity stage does. Request variables for the models are the total copper content or the copper bound to the organic matter
and the meteorological data.
Electronic Publication 相似文献
Dibenzofuran (DF) is formed from phenol and benzene in combustion gas exhaust streams prior to particle collection equipment. Subsequent chlorination at lower temperatures on particle surfaces is a potential source of chlorinated dibenzofuran (CDF). Gas streams containing 8% O2 and approximately 0.1% DF vapor were passed through particle beds containing copper (II) chloride (0.5% Cu, mass) at temperatures ranging from 200 to 400 °C to investigate the potential for CDF formation during particle collection. Experiment duration was sufficient to provide an excess amount of DF (DF/Cu=3). The efficiency of DF chlorination by CuCl2 and the distribution of CDF products were measured, with effects of temperature, gas velocity, and experiment duration assessed. Results of a more limited investigation of dibenzo-p-dioxin (DD) chlorination by CuCl2 to form chlorinated DD (CDD) products are also presented.
The efficiency of DF/DD chlorination by CuCl2 was high, both in terms of CuCl2 utilization and DF/DD conversion. Total yields of Cl on CDF/CDD products of up to 0.5 mole Cl per mole CuCl2 were observed between 200 and 300 °C; this suggests that nearly 100% CuCl2 was utilized, assuming a conversion of two moles of CuCl2 to CuCl per mole Cl added to DD/DF. In a short duration experiment (DF/Cu=0.3), nearly 100% DF adsorption and conversion to CDF was achieved. The degree of CDF chlorination was strongly dependent on gas velocity. At high gas velocity, corresponding to a gas–particle contact time of 0.3 s, mono-CDF (MCDF) yield was largest, with yields decreasing with increasing CDF chlorination. At low gas velocity, corresponding to a gas–particle contact time of 5 s, octa-CDF yield was largest. DF/DD chlorination was strongly favored at lateral sites, with the predominant CDF/CDD isomers within each homologue group those containing Cl substituents at only the 2,3,7,8 positions. At the higher temperatures and lower gas velocities studied, however, broader isomer distributions, particularly of the less CDD/CDF products, were observed, likely due to preferential destruction of the 2,3,7,8 congeners. 相似文献
The predictive accuracy of using the one-dimensional advection–dispersion equation to evaluate the fate and transport of solute in a soil column is usually dependent on the proper determination of chemical retardation factors. Typically, the distribution coefficient (Kd) obtained by fitting the linear sorption isotherm has been extensively used to consider general geochemical reactions on solute transport in a low-concentration range. However, the linear distribution coefficient cannot be adequately utilized to describe the solute fate at a higher concentration level. This study employed the nonlinear equilibrium-controlled sorption parameters to determine the retardation factor used in column leaching experiments. Copper and cadmium transportation in a lateritic silty-clay soil column was examined. Through the explicit finite-difference calculations with a third-order total-variation-diminishing (TVD) numerical solution scheme, all results of the theoretical copper and cadmium breakthrough curves (BTCs) simulated by using the Freundlich nonlinear retardation factors revealed good agreement with the experimental observations. 相似文献
The electrical instrumentation control systems (EICS) ‘As-built’ documentations of a copper mine were found to possess a significant errors and omissions, which hindered the asset owner’s ability to undertake effective and efficient operations and maintenance. A Systems Information Model (SIM) was used to retrospectively create a connected system to ensure all physical equipment and the associated connections that were constructed are modelled in an object-orientated database. In creating the SIM, the existing errors and omissions in the ‘As-built’ documentation were quantified, and cost savings that could be achieved for a future planned copper mine, with a similar design, were identified. The limitations of using conventional computer-aided-design (CAD) to design and document EICS are discussed. It is recommended that retrospectively creating a SIM can provide owners and operators with significant productivity benefits as well as ensure the asset’s integrity. The case study presented provides asset owners and operators with the empirical evidence to challenge conventional thinking surrounding the design, engineering and documentation of EICS using CAD and alternatively consider the use of SIM. 相似文献