Adsorption of Cu (II) and Ni (II) Ions from Solution onto Calcium Alginate Beads

The objective of this study was to investigate the biosorption of Cu (II) and Ni (II) ions from aqueous solution by calcium alginate beads. The effects of solution pH, contact time and initial metal ion concentration were evaluated. The results showed that maximum Cu (II) removal (93.10%) occurred at pH of 9.0, contact time of 120 minutes and initial ion concentration of 10 mg/L while that of Ni (II) was 94.6%, which was achieved at pH of 8.0, contact time of 120 minutes and initial ion concentration of 10 mg/L. The equilibrium data fitted well to the Langmuir Isotherm indicating that the process is a monolayer adsorption. The coefficients of determination, R2, values for the Langmuir Isotherm were 0.9799 and 0.9822 respectively for Cu (II) and Ni (II) ions. The values of the maximum biosorption capacity, Qo, were 10.79 and 6.25 mgg-1 respectively. The kinetic data also revealed that the sorption process could best be described by the pseudo – second order kinetic model. The R2 values for the pseudo – second order kinetic plots for Cu (II) and Ni (II) were 0.9988 and 0.9969 respectively. These values were higher than those for the pseudo – first order plots. The values of the biosorption capacity qe obtained from the pseudo – second order plots were very close to the experimental values of qe indicating that the biosorption process follows the second order kinetics. This study has therefore shown that calcium alginate beads can be used for the removal of Cu (II) and Ni (II) ions from wastewaters. Keywords: Keywords: Adsorption, Calcium alginate, Isotherm, Langmuir, Pseudo- first order, Pseudo-second orde

Physico-chemical parameters of soil in some selected dumpsites in Zaria and its environs

Physico-chemical parameters of soil were found to have influence on the availability of heavy metals in plants. pH values recorded in the control site ranges from 7.8 to 9.2 indicating that all the soils studied were alkaline. The control site has a value of 7.16. The conductivity values range from 4.2 x 10-2 to 4.0x105μScm-1 . The highest conductivity value was recorded in site B, while site D had the least value. Moisture content in the 10 dumpsites studied ranged from 17.87 to 82.49%. Organic matter contents in the dumpsites ranged from 3.20 to 5.30% and are higher than values obtained for uncontaminated/control site. These higher values may be due to the aging of the dumpsites. The cation exchange capacity values ranged from 132.83(R) to 469.5(G)CmolKg-1. These values are reasonably high due to the relatively higher conductivity values obtained in the dumpsites and this may also affect the bioavailability of the heavy metals in plants. Correlation analysis revealed that pH, electrical conductivity and moisture content were negatively correlated.Keywords: Bioavailability, dumpsite, heavy metal, physico-chemical parameter, Zari

Assessment of trace metals in sewage water and sludge from River Kubanni drainage basin

The concentrations of trace metals in sewage water and sludge samples from River Kubanni drainage basin in Zaria City, Nigeria were investigated in this study. The drainage basin is utilized as a source for irrigation water, during dry seasons. The sewage water quality characteristics in three month sampling periods, that is, February - April, 2008 (peak of dry season and period of intensive usage of the sewage water), the speciation of metals in the sewage sludge from the drainage basin, and the risk to sewage water column contamination were evaluated. The sewage water quality characteristics were mostly beyond the recommended irrigation water standards by the food and agriculture organization (FAO) and United State environmental protection agency (USEPA) except for zinc and nickel. In addition, the average values of Cd, Cu, Pb, Cl- and NO3- in sewage water samples analyzed were higher than the respective reference values for irrigation water. To study the speciation of metals in sewage sludge, five metals (Zn, Ni, Cu, Pb and Cd) in the sludge were subjected to sequential extractions. The metals analyzed were distributed in both the non-residual and residual phases. Total extractable trace metals in sewage sludge were: Zn (403.3 mg/kg dry weight), Ni (184.2 mg/kg dry weight), Cu (303.4 mg/kg dry weight), Pb (129.0 mg/kg dry weight) and Cd (19.7 mg/kg dry weight). However, there was low risk to sewage water contamination based on the calculated individual contamination factors (ICF) obtained for sewage sludge from the trace metal sequential extractions. From the calculated individual contamination factors, Ni and Zn followed by Cd and Pb posed the highest risk to sewage water contamination. Based on this study, the human health is at risk, since sewage water from the drainage basin has been the source for irrigation water during dry seasons, which might lead to trace metal ingestion by soil and subsequently by vegetables. Thus, this might become important pathways of human exposure to metal contamination.Key words: Trace metals, speciation, contamination factor, sewage water and sludge

Biosorption of Zn (II) ions from aqueous solution by immobilized Aspergillus fumigatus

The objective of this study was to investigate the biosorption of Zn (II) from aqueous solution by Aspergillus fumigatus immobilized in calcium alginate. The effects of adsorbent dosage, initial solution pH, contact time and initial Zn (II) concentrations were investigated. Results were fitted to the Langmuir isotherm. The results showed an increase in biosorption efficiency with increase in biosorbent dosage. The optimum pH of adsorption was 5.0 while the maximum adsorption was achieved within 10 minutes at initial Zn (II) concentration of 1 mg/L. The experimental results showed a high R2 (0.9070) value for the Langmuir isotherm. This therefore suggests that it is a monolayer adsorption. The maximum biosorption capacity was 3.55 mgg-1. These results indicate that zinc metal removal by biomass of Aspergillus fumigatus immobilized in alginate is a low cost wastewater treatment option and can be effectively used in small scale treatment plants.Keywords: Biosorption, Aspergillus fumigatus, Adsorbent, Alginate, Isotherm, Langmui

Levels of trace metals in soil and vegetation along major and minor roads in metropolitan city of Kaduna, Nigeria

Sample of soil and plant (Sida acuta burm F.) were collected from 30 sites of 24 roads. The samples were analyzed for Pb, Cd, Zn, Cu and Mn using flame atomic absorption spectrophotometry. The soilphysico-chemical parameter, pH and particle size distribution was also determined. Levels of Pb, Cd,Zn, Cu and Mn in soil were 15.28 – 76.92, 1.96 – 9.80, 41.66 – 237.96, 1.60 – 4.88 and 76.00 – 132.00mg/kg dry weight, respectively. Results of concentrations in plants ranged were from trace – 32.37, 4.88 – 14.93, 27.78 – 185.19, 1.67 – 3.89 and 20.00 – 110.00 mg/kg dry weight for Pb, Cd, Zn, Cu and Mn,respectively. The soil pH was from 6.22 – 8.44 while sand and loamy sandy textural classes constitute the soil samples. For both experimental soil and plant samples, the mean concentrations were found to follow the decreasing orders; Zn > Mn > Pb > Cu > Cd and Zn > Mn > Pb > Cd > Cu, respectively. Mild correlation between traffic density and metals in samples with the exception of plant Pb content,suggest that automobile emission couple with waste dispose along the roads remain a threat. The findings in general indicate the levels of metals in soil and plant samples were within the EU limits withthe exception of Cd. In addition, the high level of Cd appears to reach pollution levels and metal dynamics up the food chain is highly possible

Insight from the study of acidity and reactivity of Cr2O3 catalyst in propane dehydrogenation: a computational approach

By converting low-value commodity fuels into high-value products, like polymer precursors, chemical and other intermediates, the dehydrogenation of light paraffin (such as ethane and propane) into olefins, can add significant value to the refining processes that generate propane. In this study, the parameterised method 3 (PM3) approximation of semi empirical theory was employed to study the acidity and reactivity of chromium (III) oxide catalyst in the dehydrogenation of propane into propylene. Ammonia and pyridine were used computationally as molecular probes for the evaluation of the Lewis acidity of the catalyst sites. The propane adsorption and dissociation activation energies were also evaluated. The study showed that the chromium sites are highly acidic and reactive compared to the oxygen sites. In particular, the study showed that the chromium site is the main active site in the promotion of propane dehydrogenation into propylene, over chromium (III) oxide catalyst. Keywords: Acidity, Reactivity, Dehydrogenation, Propane, Chromium

Synthesis, Spectroscopic Studies and Antifungal Activity of 7 -amino-4-methyl-quinolin-2(1H)-one

The synthesis of 7-amino-4-methyl-quinolin-2(1H)-one has been successfully carried out, and its structural characterization was perfumed using Fourier Transformed Infrared (FT-IR) and Nuclear magnetic resonance (1H and 13C-NMR) spectroscopic techniques. The compound obtained was off white in colour with percentage yield of 47 and Melting point of 269-272oC. It shows poor solubility in polar and non polar solvents at room temperature but soluble in hot DMSO and DMF. Antifungal evaluation of the compound against a clinical isolate of the fungal strain Candida albican with a standard antifungal drug Terbinafine as a positive control demonstrate moderate inhibition of the growth of the organisms with a range of 18.0mm - 20.1mm