Dynamics of zinc sorption from aqueous matrices using plantain (Musa sp.) peel biomass

The influence of climate change on freshwater resources has undoubtedly affected the availability and quality of freshwater resources. However, the demand for water for agricultural, domestic, industrial and recreational purposes increases by the day globally. The need for remediation and reuse of large volumes of industrial wastewaters being generated globally therefore cannot be over-emphasized. The potential ability of plantain peel (Musa sp.) biomass to remove metal ions (Zn2+) from aqueous matrices was studied. Influence of contact time, adsorbent weight, pH, metal concentration, temperature and shaking speed were investigated. Physico-chemical characterization (proximate and infra-red spectroscopic analyses) of the biomass was carried out to elucidate information on adsorption mechanisms. Desorption studies were also performed to determine possible recovery potential of Zn2+ and the re-usability of the biomass. Zn2+ adsorption increased with increasing metal concentration in solution, adsorbent weight and contact period. Optimal pH value for adsorption was 3 after which Zn2+ uptake decreased. Corresponding values for contact time, biomass weight and Zn2+ concentration were 150 min, 24 g/L and 600 mg/L, respectively. Experimental data fitted into Freundlich’s isotherm. Carboxylic and hydroxyl groups were among the prominent functional groups on the surface of the biomass. Desorption of Zn2+ from the biomass was less than 10%. Alternative compounds may be further investigated to improve on metal desorption from plantain peel biomass. This cannot be over-emphasized if the several advantages of this biomass (lesser cost than for synthetic resins, abundance and biodegradability) will be utilized for industrial applicability especially in emerging economies like Africa.Key words: Adsorption, zinc, isotherms, waste utilization, wastewaters

Utilization of maize (Zea mays) cob as an adsorbent for lead (II) removal from aqueous solutions and industrial effluents

Maize cob was used as an adsorbent in order to evaluate its potential for the removal of lead from aqueous solutions and effluents from battery and paint industries with Dowex (synthetic resin) as control. Experimental data were analyzed in terms of Freundlich isotherm model. Equilibrium was attained at 2 h and adsorption rate constants for maize cob and dowex were 7.26 x 10-2 and 7.58 x 10-2 min-1, respectively. Equilibrium pH value was 6; shaking at 150 rpm enhanced adsorption with maximum adsorption by both adsorbents in battery and paint effluents. Optimal weight at equilibrium for the adsorbents in Pb2+ solution was 16 mg/L of solution. Pb2+ removal by maize cob from battery effluent was 99.99% while it was 47.38% for Dowex. Corresponding values from paint effluents were 66.16 and 27.83%. The study concludes that maize cob has great potentials to remove Pb2+ from industrial effluents

Assessment of the phytoremediation potential of Panicum maximum (guinea grass) for selected heavy metal removal from contaminated soils

Non-vascular plants have potential for rapid uptake of metals, but are rarely used for phytoremediation because of their short life cycle. This property can however be advantageously used in a number of metal removal cycles within a short time. The selection of promising plants is critical to success of phytoremediation. The potential for heavy metal uptake by Panicum maximum a non-vascular plant was investigated using pot plant experiments. Seventy-two (72) pots of 7 L capacity were each filled with 5 kg of mixed soil collected from the Fadama (fertile soil) and College of Animal Sciences and Livestock Production farms (less fertile) of the University of Agriculture Abeokuta, Ogun State Nigeria. The pots were divided into six groups of twelve pots each. Each of the group of 12 pots was further divided into three groups of four pots each, in which P. maximum were planted. Five of the six groups were treated with 20, 50, 75, 100 and 120 ppm each of Pb2+, Cr3+ and Cd2+ and the sixth served as control. Levels of Pb2+ decreased from 1.40 to 1.05 µg/g and 1.57 to 1.30 µg/g in soils treated with 20 and 120 ppm of Pb2+, respectively. Generally there was increase in Pb2+ uptake by the different tissues of P. maximum ranging between 0.21 to 0.38 µg/g, 0.18 to 0.30 µg/g, and 0.09 to 0.18 µg/g in root, stem and foliage, respectively. Corresponding bioaccumulation factors (BAF) ranged between 0.21 to 0.45, 0.17 to 0.35 and 0.08 to 0.21. Metal uptake followed similar trends for Cr3+ and Cd2+ in plant tissues. The BAF values for Cr3+ ranged between 0.31 to 0.69 in root, 0.17 to 0.52 in stem and 0.07 to 0.34 in foliage. Similar values for Cd2+ were 0.14 to 0.53, 0.10 to 0.44 and 0.05 to 0.37. Accumulation of heavy metals in P. maximum ranged from 13 to 45%, Pb2+; 13 to 65%, Cr3+ and 11 to 52%, Cd2+ of the soil concentration level with tissue abundance decreasing in the order Cr3+ > Pb2+ > Cd2+. Furthermore, the concentration of metals in P. maximum tissues decreased in the order root > stem > foliage. The phytoremediation of Pb2+, Cr3+ and Cd2+contaminated soils with P. maximum seems to be promising under the conditions of the experiment. Obvious signs of phyto-toxicity however appeared in plants exposed to 120 ppm Pb2+ and Cd2+ at day twenty-three, suggesting that P. maximum may be a moderate metal accumulator.Keywords: phytoremediation, heavy metals, uptake, tissues, accumulatorAfrican Journal of Biotechnology, Vol 13(19), 1979-198

Veterinary pharmaceuticals in aqueous systems and associated effects: an update

Environmental studies have shown that pharmaceuticals can contaminate aqueous matrices, such as groundwater, surface water, sediment as well as aquatic flora and fauna. Effluents from sewage and wastewater treatment plants, pharmaceutical industries and hospitals have been implicated in such contamination. Recent studies have however revealed significant concentrations of pharmaceuticals in wastewater from animal facilities in proximal aquatic habitats. Furthermore, epidemiological studies have shown a consistent positive correlation between exposure to some drugs of veterinary importance and increased adverse effects in aquatic biota largely due to induction of endocrine disruption, antibiotic resistance, neurotoxicity, genotoxicity and oxidative stress. The aquatic habitats and associated biota are important in the maintenance of global ecosystem and food chain. For this reason, anything that compromises the integrity and functions of the aquatic environment may lead to major upset in the world’s ecosystems. Therefore, knowledge about this route of exposure cannot be neglected and monitoring of their occurrence in the environment is required. This review focuses on scientific evidence that link the presence of pharmaceuticals in aqueous matrices to animal production facilities and presents means to reduce the occurrence of veterinary pharmaceutical residues in the aquatic habitats

Abatement of Cr6+ and Pb2+ from aqueous matrices using sugarcane biomass

Abatement of Cr6+ and Pb2+ from aqueous matrices using sugarcane biomass 4th International Ecosummit, Columbus, OH, 30 September-5 October 201

Investigation into the bacterial pollution levels at various sites along the Diep and Plankenburg river systems, 3 Western Cape, South Africa.

This study sought to investigate and compare bacterial contamination levels at six different sites along the Diep and Plankenburg river systems in the Western Cape, South Africa. Surface water and sediment samples were collected monthly from the six selected sampling sites along both river courses between January 2014 and December 2014 and were evaluated for bacterial contaminants. Microbial isolation, characterisation and identification were done using conventional techniques (serial dilution, Gram staining, and biochemical testing) and molecular identification techniques (polymerase chain reaction and DNA sequencing). A total of 19 bacterial isolates belonging to the genera Raoultella, Bacillus, Pseudomonas, Klebsiella, Escherichia, Enterobacter, Exiguobacterium, Acinetobacter, Serratia, Aeromonas, Staphylococcus and Citrobacter were isolated from the surface water and sediment samples at the end of the survey. Higher microbial load was obtained from sediment samples compared to surface water samples. Seasonal variation was also observed in terms of microbial counts. Higher microbial counts were obtained during summer sampling time compared to winter sampling time. The most contaminated site was located on Plankenburg River with average bacterial counts ranging between 3.1 × 10(5)-6.9 × 10(8) CFU/ml and 3.9 × 10(6)-2.88 × 10(9) CFU/ml from surface water and sediment, respectively, recorded at this site during winter and summer. Although lower microbial counts were recorded along the Diep River course, most of the bacterial counts recorded along both rivers exceeded the acceptable maximum limits for river water

Zinc abatement from simulated and industrial wastewaters using sugarcane biomass

The use of heavy metals and their compounds in industrial applications has resulted in their occurrence in various environmental media including water bodies. Conventional methods of heavy metal removal from wastewaters are very expensive, when available, especially in developing countries. This study therefore assessed the potential of sugarcane biomass to remove zinc from standard solutions and industrial (paint and textile) wastewaters. Parameters studied include contact time, biomass weight, metal concentration, pH, agitation, temperature and particle size. Physico-chemical characteristics of biomass were also studied. Adsorption of zinc increased with increases in contact time, biomass weight, pH and agitation speed, while adsorption decreased with increasing particle size and for temperatures above 50o C. Sugarcane biomass was responsible for over 90% adsorption of Zn2+ in both effluents. Under conditions of agitation, 100% adsorption was achieved. Percentage ash, particle density, cation exchange capacity (CEC) and porosity are important physico-chemical properties which influenced Zn2+ adsorption. Percentage ash and CEC are positively correlated to percentage adsorption while particle density and porosity are negatively correlated. Percentage desorption was over 90 for both effluents. Sugarcane biomass is therefore a potential alternative to expensive synthetic resins. Its biodegradability makes disposal environmentally friendly. However, there is the need to further study the biomass in flow-through systems for industrial applicability.International Foundation for Science (IFS), Sweden, through Research Grant No. W/4264-

Polycyclic aromatic hydrocarbons (pahs) in food and environmental samples: an overview

Polycyclic aromatic hydrocarbons (PAHs) have been widely reported as a class of ubiquitous chemicals in different matrices. Health implications of these pollutants include carcinogenicity and mutagenicity amongst others. The need for effective measurement techniques of these compounds therefore becomes imperative. This paper reviews sources of PAHs into the environment, exposure routes and effects on humans. Furthermore, an overview of different measurement techniques in environmental and food samples is also presented. Extraction methods that have been applied for PAHs quantification include solidphase extraction (SPE), solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE), liquid-phase microextraction (LPME), liquid-liquid extraction (LLE), accelerated solvent extraction (ASE) and solid-liquid extraction. Most commonly used analytical methods are gas chromatography-mass spectrometry (GC/MS), gas chromatography- flame ionization detection (GC/FID), high performance liquid chromatography-fluorescence detection (HPLC/FD) and high performance liquid chromatography- ultra violet detection (HPLC/UV). Levels reported in different media suggest global need for PAHs monitoring in foods and environmental samples. KEYWORDS: Extraction, analysis, polycyclic aromatic hydrocarbons, food, soil and water

Determination of polycyclic aromatic hydrocarbons [PAHs] in processed meat products using gas chromatography – Flame ionization detector

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in smoked, grilled and boiled meats were determined using gas chromatography – flame ionization detector (GC–FID). PAHs in the processed meats were extracted in n-hexane after hydrolysis with methanolic KOH. Clean-up was achieved using solid phase extraction in neutral-Si/basic-Si/acidic-Si/neutral-Si frits. The fractions, benzo[k]fluoranthene (BkP), benzo[a]pyrene (BaP), indeno[123-cd]pyrene (IP) and benzo[ghi]perylene (BghiP) were separated and quantified using GC–FID. The method and instrument limits of detections were 0.1, 0.1, 0.2, 0.3 lg/kg and 0.5, 0.5, 1.0, 1.5 lg/kg, respectively, for BkP, BaP, IP and BghiP. The method’s recovery and precision generally varied between 83.69% and 94.25% with relative standard deviation (RSD) of 3.18–15.60%; and 90.38–96.71% with relative standard deviation (RSD) of 1.82–12.87% respectively. The concentration of BkP, BaP, IP and BghiP in smoked, grilled and boiled meat samples were ranged 0.64–31.54 lg/kg, 0.07–7.04 lg/kg, 0.09–15.03, 0.51–46.67 lg/kg and 0.01–5.11 lg/kg, respectivel

Utilization of maize (Zea mays) cob as an adsorbent for lead (II) removal from aqueous solutions and industrial effluents

Maize cob was used as an adsorbent in order to evaluate its potential for the removal of lead from aqueous solutions and effluents from battery and paint industries with Dowex (synthetic resin) as control. Experimental data were analyzed in terms of Freundlich isotherm model. Equilibrium was attained at 2 h and adsorption rate constants for maize cob and dowex were 7.26 x 10-2 and 7.58 x 10-2 min-1, respectively. Equilibrium pH value was 6; shaking at 150 rpm enhanced adsorption with maximum adsorption by both adsorbents in battery and paint effluents. Optimal weight at equilibrium for the adsorbents in Pb2+ solution was 16 mg/L of solution. Pb2+ removal by maize cob from battery effluent was 99.99% while it was 47.38% for Dowex. Corresponding values from paint effluents were 66.16 and 27.83%. The study concludes that maize cob has great potentials to remove Pb2+ from industrial effluents