Performance of NiFe 2

Investigation into the reduction of Cr(VI) in aqueous solution was carried out through some batch photocatalytic studies. The photocatalysts used were silica coated nickel ferrite nanoparticles (NiFe2O4-SiO2), nickel ferrite titanium dioxide (NiFe2O4-TiO2), nickel ferrite silica titanium dioxide (NiFe2O4-SiO2-TiO2), and titanium dioxide (TiO2). The characterization of the materials prepared via stepwise synthesis using coprecipitation and sol-gel methods were carried out with the aid of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The reduction efficiency was studied as a function of pH, photocatalyst dose, and contact time. The effects of silica interlayer between the magnetic photocatalyst materials reveal that reduction efficiency of NiFe2O4-SiO2-TiO2 towards Cr(VI) was higher than that of NiFe2O4-TiO2. However, TiO2 was observed to have the highest reduction efficiency at all batch photocatalytic experiments. Kinetics study shows that photocatalytic reduction of Cr(VI) obeyed Langmuir-Hinshelwood model and first-order rate kinetics. Regenerability study also suggested that the photocatalyst materials can be reused

Uptake of Zn2+ and As3+ from Wastewater by Adsorption onto Imine Functionalized Magnetic Nanoparticles

In this paper, imine functionalized magnetic nanoparticles (MNP-Maph) were employed to aqueous solutions for the uptake of Zn(II) and As(III). Characterization of the material showed the successful synthesis of this material. Factors affecting the uptake of metal ions in aqueous solution such as change in pH, time, adsorbent dose, adsorbate concentration, and temperature were investigated and optimized to determine the best experimental conditions for the effective adsorption of Zn(II) and As(III) from wastewater samples. The adsorption capacity of MNP-Maph followed similar patterns as that of amine functionalized magnetic nanoparticles (MNP-NH2) for the uptake of both metal ions from aqueous solution when solution pH was varied. Higher pH values favored the uptake of Zn(II) and As(III) by using both adsorbents. Also, increasing the contact time and temperature yielded a higher uptake of Zn(II) and As(III). Both processes can best be described with a pseudo-second order kinetic model, while the Langmuir maximum adsorption capacity (qm) for Zn(II) increased from 35.83 to 54.53 mg g−1, and for As(III) from 50.08 to 57.60 mg g−1. Of note is that the qm of As(III) was higher than that of Zn(II) because of the lower concentration of As(III) in solution compared to that of Zn(II), and thermodynamic parameters indicated that the adsorption processes were heat absorbing and rapid in nature. Experiments to evaluate if the adsorbent could be recycled showed excellent recyclability capacity of MNP-Maph after seven runs. Lastly, application of MNP-Maph for the uptake of Zn(II) and As(III) from municipal wastewater samples showed remarkable sorption performance confirming the potential of imine functionalized magnetic nanoparticles as an excellent adsorbent for the uptake of metal ions from aqueous solutions

Petroleum Hydrocarbon Profiles of Water and Sediment of Algoa Bay, Eastern Cape, South Africa

Petroleum hydrocarbon profiles of water and sediment samples of Algoa Bay in the Eastern Cape Province of South Africa were assessed using standard analytical procedures. Water (from surface and bottom levels) and sediment samples were collected from five locations in the bay from February to June 2016. Extraction of the petroleum hydrocarbons from the water and sediment samples collected was achieved using liquid-liquid and Soxhlet extraction techniques, respectively, followed by column clean up. Target compounds were analytically determined with gas chromatography–flame ionization detector (GC-FID) and quantified by integrating the areas of both the resolved and unresolved components. Physicochemical properties of the water samples were also determined on site using a SeaBird 19plusV2 CTD SBE 55 device. Estimated limit of detection, limit of quantitation and relative standard deviation for the 35 n-alkane standards ranged from 0.06 to 0.13 μg/L, 0.30 to 0.69 μg/L and 3.61 to 8.32%, respectively. Results showed that total petroleum hydrocarbon (TPH) varied from 45.07 to 307 μg/L in the water and 0.72 to 27.03 mg/kg in the sediments. The mean concentrations of TPH in both the water and sediment samples from Algoa Bay revealed a slight level of pollution. The diagnostic indices used showed that the hydrocarbons in the area were from both biogenic and anthropogenic sources. Hence, there is need for adequate regulation and control of all activities contributing to the levels of petroleum hydrocarbon in the marine environment for the safety of human, aquatic and wild lives in the area

In-Vitro Antagonistic Characteristics of Crude Aqueous and Methanolic Extracts of Garcinia kola (Heckel) Seeds against Some Vibrio Bacteria

The methanolic and aqueous extracts of Garcinia kola seeds were screened for their anti-Vibrio activities against 50 Vibrio isolates obtained from wastewater final effluents in the Eastern Cape Province, South Africa. The crude extracts at 10 mg/mL exhibited appreciable inhibitory activities against most of the test Vibrio isolates, with zones of inhibition ranging from 10–19 mm for methanol extract and 8–15 mm for the aqueous extracts. The minimum inhibitory concentrations (MIC) of the methanol extract varied from 0.313 to 2.5 mg/mL while that for the aqueous extract was 10 mg/mL for all the susceptible Vibrio isolates. Rate of kill assay of the methanolic extracts against three selected Vibrio species showed bacteriostatic activities against all of them achieving 58% and 60% (Vibrio vulnificus AL042); 68% and 69% (Vibrio parahaemolyticus AL049); and 70% and 78% (Vibrio fluvialis AL040) killing of the test bacteria at 3× and 4 ×MIC values, respectively, after 2 h exposure time. We conclude that Garcinia kola seeds hold promise as a potential source of therapeutic compounds of relevance in Vibrio infections management

Synthesis, characterization, antimalarial, antitrypanocidal and antimicrobial properties of gold nanoparticle

In this study, we report on the biosynthesis of gold nanoparticles (AuNPs) by using Callistemon citrinus (C. citrinus) seed extract as both reducing and capping agent as well as its characterization. Likewise, the in vitro antiparasitic activities of both biosynthesized gold nanoparticles and crude seed extract of the plant were evaluated. The formation of biosynthesized AuNPs was confirmed by a color change immediately when the seed extract was added to the gold chloride (III) solution. Characterization of the AuNPs was done using analytical tools like ultraviolet–visible spectroscopy, X–ray diffraction, scanning electron microscopy (SEM), energy dispersive X–ray (EDX), transmission electron microscopy (TEM) and Fourier transformed infra–red (FTIR). FTIR showed an absorption peak at 230 nm consistent with the absorption band for gold nanoparticles, the morphology and composition of AuNPs was ascertained by SEM and EDX micrographs; uneven spherical-shaped nanoparticles was established by SEM analysis, and an average particle size of about 37 nm was confirmed by the TEM analysis. The crude seed extracts exhibited antitrypanosoma activities with an IC50 of 11.06 µg/mL. Both the crude seed extract and AuNPs were inactive against plasmodial parasite, while the antibacterial assay showed that AuNPs is potent against gram positive and gram negative bacterial strains

Occurrences of Organochlorine Pesticides along the Course of the Buffalo River in the Eastern Cape of South Africa and Its Health Implications

Most organochlorine pesticides (OCPs) which are increasingly used in agriculture and industry are not biodegradable and thereby persist in the environment for a very long period of time. They are capable of negatively impacting the health of humans and biota when present in a higher concentration than recommended. This study evaluated the concentrations of 17 OCPs in surface water samples collected from six sampling sites along the course of the Buffalo River in Eastern Cape, South Africa, between December 2015 and May 2016. The samples were subjected to solvent extraction, followed by florisil clean up, and analyzed using gas chromatography coupled with an electron capture detector. The individual concentrations of OCPs detected ranged from <LOD to 4403 ng/L in summer and <LOD to 313 ng/L in autumn. The levels of OCPs in the study area were generally above the United State Environmental Protection Agency (USEPA) limit of 100 ng/L in all the sampling locations in the two seasons. The cancer risk assessment values were below the permissible limit of the 10−6 level, although the life average daily dose were slightly above the USEPA maximum limits of 10−4. Therefore, there is a need for the adequate regulation of agrochemical storage, use, and disposal in this province and other parts of South Africa

Terpene constituents of the aerial parts, phenolic content, antibacterial potential, free radical scavenging and antioxidant activity of Callistemon citrinus (Curtis) Skeels (Myrtaceae) from Eastern Cape Province of South Africa

Abstract Background Volatile oil from aromatic plants has been used by ancient Egyptians in embalming for the inhibition of bacterial growth and prevention of decay, Callistemon citrinus is used in traditional therapies for the treatment of bronchitis, cough, inflammation and as an antimicrobial herbs. This study examines the essential constituents of the volatile oils obtained from the aerial parts of the plant as well as its antioxidant activity, free radical scavenging, phenolic content and the antibacterial potential of the oils. Methods A portion of 500 g, 250 g and 150 g of the leaves, flowers and stems of this plant respectively were subjected to hydro-distillation process for three hours. The oils collected from the various plant parts were immediately subjected to GC-MS analysis. The overall phenolic content of the leaves oil, radical scavenging, antibacterial action and antioxidant activities of the essential oils of both the leaves and flowers of Callistemon citrinus were determined using standard methods, with free radical DPPH and ABTS as a reference antioxidant. Results Analyses of the three oils revealed a total of twenty-six components for the leaves oil representing 96.84% of the total oil composition, forty-one components for the flowers oil accounting for 98.92% of the whole composition and ten components for the stem oil amounting to 99.98% of the entire oil constituents. The dominant compounds in the leaves oil were eucalyptol (48.98%) and α-terpineol (8.01%), while α-eudesmol (12.93%), caryophyllene (11.89%), (−)-bornyl-acetate (10.02%) and eucalyptol (8.11%) were the main constituents of the flowers oil. In the same vein, the leading constituents in the stems oil were eucalyptol (56.00%) and α-pinene (31.03%). The antioxidant capacities of both the leaves and flowers oils of the plant were evaluated and their IC50 were (1.49 and 1.13) for DPPH and (0.14 and 0.03) for ABTS assay respectively. The antibacterial activities of the oils from the (leaves and flowers) were also examined and were found to have wide range of activities against the bacterial strains used in this study. Conclusion Observations drawn from this experiment shows clearly that the leaves and flowers of Callistemon citrinus possess phenolic compounds and cyclic ether of several pharmacological behaviors

Ethanol extract and chromatographic fractions of Tamarindus indica stem bark inhibits Newcastle disease virus replication

Context: The plethora of ethnomedicinal applications of Tamarindus indica Linn. (Leguminosae), tamarind, includes treatment of human and livestock ailments; preparations are recognized antipyretics in fevers, laxatives and carminatives. African folklore has various applications of tamarind. However, in Nyasaland, domestic fowl are fed with preparations for prophylactic properties. Objectives: The objective of this study is to evaluate the antiviral properties of T. indica extract. Materials and methods: Tamarindus indica stem bark was extracted through ethanol maceration over 24 h, and the crude extract was fractionated by gravity-propelled column chromatography. Newcastle disease virus (NDV) inhibitory activity of extract and fractions were evaluated in vivo using 10-d-old embryonated chicken egg (ECE) as the medium for virus cultivation and antivirus assay. About 240 ECE were grouped into eight (three controls and five experimental) and, 200 μL of the extract and fractions respectively inoculated into NDV pre-infected eggs and incubated at 37 °C. Allantoic fluid was harvested 5 d post-virus infection and assayed for haemagglutination (HA). Results: Anti-NDV assessment showed 62.5 mg/mL of crude extract and fractions: TiA, TiC and TiD to yield a HA titre of 1:128 each, while TiB showed 1:64 HA titre. At 125 mg/mL, a titre of 1:16 was recorded against TiB and TiD and, 1:8 against TiA. Similarly, crude extract and TiC, each recorded 1:4 HA titre. However, the minimum concentrations of extract and fraction for virus inactivation were 0.24 mg/mL and 0.49 mg/mL, respectively. Conclusion: The antiviral activity shown by T. indica portends novel antiviral drugs and, perhaps, as scaffold for new drugs