Phytoremediation of Heavy Metals ( Cu , Zn , and PB ) Contaminated Water Using Water Hyacinth ( Eichornia Crassipes ) 1
Water samples contaminated with heavy metals (Zn, Cu and Pb) were subjected to phytoremediation method using water hyacinth (E. crassipes) for the period of 8 weeks. The study involved the preparation of the heavy metals solutions in different concentrations (their pH values supplemented) into eight 40L plastic containers, with six containers having the solutions of heavy metals (Zn, Cu and Pb in their replicates) while two plastic containers served as the control. Thereafter, the experiment was monitored and analyzed for 8 weeks for metal accumulation by the plant. Water analysis was carried out to know the concentration of heavy metals present in the water during these periods and the plants were also analyzed using Atomic Absorption Spectrophotometer. The results obtained were further interpreted using SPSS (T-test) to determine the mean concentration obtained from week 1 to week 8.The results obtained for Zn were 0.28 ,0.23 ,0.13 ,0.04 ,BDL,0.02 ,BDL,BDL .Also the results obtained for Cu from week 1 to week 8 were 0.04 ,0.07 ,0.03, BDL ,BDL ,BDL ,BDL ,BDL. More so, the results obtained for Pb from week 1 to week 8 were 0.13, 0.45, 0.05, BDL, BDL, BDL, BDL, BDL. At the end of the 8 weeks of remediation, it was observed that the concentrations of the metals in the water were below the detection limit but accumulated in the plant. Also, the results of the Bioconcentration factor (BCF) showed that the investigated plant (E.crassipes) hyperaccummulated Zn than other heavy metals. Therefore, heavy metal uptake by E. crassipes using phytoremediation technology seems to be a prosperous way to remediate heavy metal contaminated environment.
A review on the phytoremediation of petroleum hydrocarbon.
Oil spillage as a result of petroleum industry activities and pipe-line vandalization by saboteurs is a frequent occurrence in oil-producing regions of the world. Conventional oil spill clean-up techniques involve physical and chemical processes that do more damage to the aquatic ecosystem than the oil spill itself. Consequently, the need arises to evolve or develop a more environment-friendly technique that will not only clean-up the environment but also restore the aquatic ecosystem to its status before the oil spill. Phytoremediation, which involves the use of plant to detoxify polluted site, appears to be promising in this regard. It is environment-friendly as well as cost-effective but may take more time than the conventional methods because it is a natural process.
Techno-economic analysis of chemical looping combustion with humid air turbine power cycle
Abstract Power generation from fossil fuel-fired power plant is the largest single source of CO2 emission. CO2 emission contributes to climate change. On the other hand, renewable energy is hindered by complex constraints in dealing with large scale application and high price. Power generation from fossil fuels with CO2 capture is therefore necessary to meet the increasing energy demand, and reduce the emission of CO2. This paper presents a process simulation and economic analysis of the chemical looping combustion (CLC) integrated with humid air turbine (HAT) cycle for natural gas-fired power plant with CO2 capture. The study shows that the CLC–HAT including CO2 capture has a thermal efficiency of 57% at oxidizing temperature of 1200 °C and reducer inlet temperature of 530 °C. The economic evaluation shows that the 50 MWth plant with a projected lifetime of 30 years will have a payback period of 7 years and 6 years for conventional HAT and CLC–HAT cycles respectively. The analysis indicates that CLC–HAT process has a high potential to be commercialised.