Evaluating the Potential Effectiveness of Moringa oleifera Seeds Biomass as an Adsorbent in the Removal of Copper (Cu) in Water

This study was based on the evaluation of the potential effectiveness of Moringa oleifera seeds biomass as a biosorbent in the removal of copper (Cu) in water which was justified by the level of toxicity, environmental unfriendliness and costly nature of chemical coagulants presently used. Fourier transform infrared (FTIR) analysis was used to identify the Moringa oleifera seeds biomass functional groups present in the adsorption of metal ions and found to be the carboxylic acid and amine functional groups (-COOH and -NH). The effects of contact time, adsorbent dosage, metal ion concentration and pH were studied. The maximum adsorption capacity at pH 5, room temperature and 0.8 g dosage was 70% for Cu(II). The adsorption data fitted better to the Langmuir than the Freundlich models as the sorption capacity (qm) of Moringa oleifera seeds biomass for Cu(II) was 3.64 mg/g. The separation factor (RL) was within the range of 0 and 1 which showed that the Cu(II) biosorption processes were favourable for Moringa oleifera biosorbent. The results showed that Moringa oleifera seed biomass is an effective adsorbent in the removal of the studied heavy metals in water. The effective pH for the Cu(II) removal was 5.0 as equilibrium was achieved practically in 35 min. The quantitative analysis of defatted Moringa oleifera should be studied in order to have a fair mixing ratio between Moringa oleifera seeds biomass and the adsorbate. There is also the ardent need to work on environmentally friendly disposal of adsorbent after saturation of adsorbent by analyte to avoid secondary pollution.

Phytochemical and antioxidant properties of different solvent extracts of Kirkia wilmsii tubers

Objective:To determine suitable phytochemical extraction solvents,screen for phytochemicals,determine the total phenol and flavonoid contents and the antioxidant activities of different solvent extracts of Kirkia wilmsii(K.wilmsii),an ethnomedicine in South Africa.Methods:Extractions were performed from dried tubers of the K.wilmsii plant,using several solvents and varying extraction times.Extract yields were determined and suitable extraction solvents were selected.Total phenol and flavonoid contents of the extracts were determined spectrophotometrically using gallic acid and quercetin as standards.The free radical scavenging activity of the extracts was investigated using l,l-diphenyl-2-picrylhydrazyl radical.Results:Phytochemical screening confirmed the presence of phenolics,flavonoids,terpenoids,tannins,cardenolide deoxy sugars and reducing sugars.Of the 12 solvent extracts used,six gave yields higher than 5%,while the other six gave yields less than 1%.The highest extract yield of 52.9%was obtained using 80%methanol while the lowest yield of 7.3%was obtained using ethanol at 60 min.The 80%methanol,methanol/chloroform/water(12:5:3)and 60%methanol extracts were significantly higher than those of ethanol,methanol and water(P < 0.05).Total phenolic content recorded extracts ranged from(45.32 ± 0.50) to(122.84 ± 0.31) mg gallic acid equivalent per gram.A maximum total flavonoid content of(917.02 ± 0.10) mg quercetin equivalent per gram and a minimum of(206.26 ± 0.10) mg quercetin equivalent per gram were recorded for methanol and water,respectively.The flavonoid content for methanol was significantly higher than all the other extracts(P < 0.05).The scavenging profiles of K.wilmsii extracts were significantly lower(P < 0.05) than that of ascorbic acid and IC50 values ranged from 129.94 μg/mL for methanol to 225.04 μg/mL for water.An IC50 value of 56.52μg/mL was obtained with ascorbic acid.Conclusions:Ethanol,methanol,methanol/chloroform/water,80%methanol,60%methanol and water can be used as suitable phytochemical extraction solvents for K.wilmsii tubers.Total phenolic content and total flavonoid content analysis proved the presence of high levels of phenolic compounds as well as flavonoids.The presence of phenols and flavonoid could be responsible for the radical scavenging activities observed.