Borassus aethiopum shell-based activated carbon as efficient adsorbent for carbofuran

ABSTRACT. Carbofuran, a pesticide applied in farmlands, often gets washed away into water bodies due to heavy rainfall and renders the water toxic. In this study, Borassus aethiopum shells-based activated carbon (BAS-AC) was prepared using CO2 and KOH as physical and chemical activating agents, respectively, which was employed as an adsorbent for the removal of carbofuran from an aqueous medium. The adsorbent was produced using the impregnation ratio of 3.28, activation temperature of 800 oC and activation time of 90 min. Textural properties and available functional groups in the adsorbent were determined using N2 adsorption-desorption isotherm and Fourier transform infrared spectroscopy, respectively. The removal efficiency was performed after optimizing the adsorption parameters and kinetics of the adsorption process was examined using a batch system. The surface area, average pore diameter and adsorption capacity of the BAS-AC were obtained as 632 m2/g, 2.97 nm and 160 mg/g, respectively. Equilibrium adsorption isotherms were fitted better by the Langmuir model than the Temkin and Freundlich models. The adsorption kinetics follow the pseudo-second-order model and the adsorbent diffusion mechanism was further studied using the intraparticle diffusion model.               KEY WORDS: Borassus aethiopum, Carbofuran, Activated carbon, Adsorption isotherm, Adsorption kinetics Bull. Chem. Soc. Ethiop. 2019, 33(3), 425-436.DOI: https://dx.doi.org/10.4314/bcse.v33i3.

Paleohydrological Reconstruction from Late Holocene Records in Interdune Lakes (N'Guigmi, Northern Bank of the Lake Chad, Niger)

An old erg covers the northern part of the Lake Chad basin. This dune landform allowed the formation of many inter- dune ponds of various sizes. Still present in certain zones where the groundwater level is high (e.g. Kanem, southern Manga), these ponds formed in the past a vast network of lacustrine microsystems, as shown by the nature and the dis- tribution of their deposits. In the Manga, these interdune deposits represent the main sedimentary records of the Holo- cene environmental succession. Their paleobiological (pollens, diatoms, ostracods) and geochemical (δ18O, δ13C, Sr/ Ca) contents are often the basis for paleoenvironmental reconstruction. On the other hand, their sedimentological char- acters are rarely exploited. This study of palustro-lacustrine deposits of the Holocene N'Guigmi lake (northern bank of the Lake Chad; Niger) is based on the relationships between the sedimentological features and the climato-hydrological fluctuations. The mineralogical parameters (e.g. calcium carbonate content, clay mineralogy) and the nature of autoch- thonous mineralization (i.e. amorphous silica, clays, calcium carbonates) can be interpreted using a straightforward hy- dro-sedimentary model. Established to explain the geochemical dynamics of Lake Chad, this model is based on a bio- geochemical cycle of the main elements (i.e. silicium, calcium) directly controlled by the local hydrological balance (i.e. rainfall/evaporation ratio). All these results show that a detailed study of sedimentological features can provide impor- tant paleohydrological informations about the regional aridification since ca 6500 14C BP

Optimization of the conditions for adsorption of fluoride in aqueous solution by carrot residue using central composite design of experiment

This study employs the use of carrot residue (CR) treated with dilute hydrochloric acid to remove fluoride ions in aqueous solution. The adsorption process parameters of pH, time of contact, adsorbent mass and initial ion concentration were optimized at ambient temperature by the use of central composite design of experiment. The CR absorbent was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microcopy (SEM). Quadratic model was used to correlate the variables to the responces obtained from the design matrix in the laboratory and analysis of variance was used to test the significance of the independent variables and their interactions. Predicted values of % adsorption at optimum conditions for commercial activated carbon (AC) which served as control and CR were validated. From the results obtained, the optimum adsorption conditions were pH 5, time of contact 96 min, mass of adsorbent 1g and initial ion concentration of 10mg/L with desirability of 1. The design predicted values and experimental values obtained for AC were 85.63% and 87.59%, while those of CR were 87.67±0.02% and 90.25±0.02% respectively. From the results obtained, it was concluded that CR was as effective and a better adsorbent for removal of fluoride ions in aqueous solution than AC. Therefore, CR is a potential alternative to AC for fluoride adsorption in aqueous solution.Keywords: Carrot Residue; Adsorption; fluoride; central composite desig

Mechanical Properties of Self-Compacting Concrete Subjected to Elevated Temperature

Self-compacting concrete flows and fills reinforcement gaps and corners of formworks without the need for vibration during the pouring process. The problem associated with the production of self-compacting concreteis the use of a high dosage of cement which necessitates the addition of supplementary cementitious materials to curtail this effect. As a result, the impact of a ternary blended pozzolanic materials on the mechanical properties of SCC exposed to extreme temperatures was investigated. A quantitative research approach was employed and an experimental design method was adopted. The materials used were cement, rice husk ash, metakaolin, and pulverized burnt bricks. Laboratory tests conducted at the hardened stage were compressive strength, weight loss, and ultrasonic pulse velocity of self-compacting concretesubjected to 200°C, 400°C, 600°C, and 800°C elevated temperatures. At 800°C elevated temperature, the result of residual compressive strength shows that SCC produced withaddition of the ternary blend at 10% had a higher value of residual compressive strength of 27.3% over the control specimens. Control specimens were found to have the least values of weight loss in comparisonto the self-compacting concreteproduced with the addition of the ternary blend. The result of residual UPV shows that self-compacting concrete produced withaddition of the ternary blend at 10% had a higher value of 8.6%over the control specimens. When self-compacting concreteis to be produced with a ternary blend of rice husk ash, metakaolin, and pulverized burnt bricksand subjected to an elevated temperature of up to 800°C, 10wt.% is the optimum cement replacementleve

Prevalence of malaria infection in children attending emergency paediatrics unit of Usmanu Danfodiyo University Teaching hospital, Sokoto - Nigeria

Background: Malaria infection in children has been of concern in this part of the world - the sub-Saharan Africa. This study was undertaken to determine the prevalence of this deadly infection in children attending Usmanu Danfodiyo University Teaching Hospital (UDUTH) Sokoto.Materials and Methods: One hundred and twenty four (124) capillary blood samples were collected from patients attending the Emergency Pediatrics Unit side laboratory. The 'gold standard' method was applied using Giemsa stain to carry out the investigation. Both thick and thin blood films were investigated for malaria parasite concentration and specie identification respectively.Results: Out of the 124 samples collected, 82 (66.13%) tested positive and 42 (33.87%) were negative for malaria infection. A total of 49 (39.52%) males and 33 (26.61%) females were positive for the infection. Of all the positive samples children within the age range of 0 – 5 years had the highest prevalence of 72 (58.06%) while the other age group of 6 – 10 years had a relatively lower prevalence of 10 (8.07%). However, using Chi-square test of independence, statistical analyses suggest that there is no statistically significant association between the distribution of malaria infection and age or gender.Conclusion P. falciparum accounted for about (84.15%) of the cases of malaria infection in the study area.Keywords: Malaria, children, prevalence, UDUTH, Chi-Square

Prevalence of malaria parasites among blood donors in Kaduna, Nigeria

Background: Transmission of malaria parasites through blood transfusion is a well-known serious risk. Screening of blood donors for malaria as recommended by WHO is currently not included in the protocols of many Nigerian blood banks. Presence of asymptomatic Plasmodium species carriers (APCs) in some northern parts of the state has already been demonstrated using rapid diagnostic tests (RDTs) and microscopic examination of Giemsa stained blood films. This research was undertaken to determine the prevalence of malaria parasites among blood donors in Kaduna state, Nigeria.Methods: A cross sectional study was conducted among the blood donors in the three selected Hospitals of Kaduna state. A well-structured questionnaire was used to collect the data regarding demographic profile. Written informed consent was obtained and questionnaire was completed by respondents selected through simple random sampling. 360 blood donors were tested for malaria parasites through microscopic examination of Giemsa stained thick and thin blood films. The data were analysed using Statistical analysis system (SAS) and statistical software for social sciences (SPSS) version 20.Results: A total of 27 (7.5%) of the blood donors had malaria parasites in their blood. Plasmodium falciparum was the only malaria parasite species encountered. There were no mixed infections and no other blood parasites were observed. The prevalence of malaria parasites in the blood donors was significantly associated with occupation (c2=24.0845, df=6, p= 0.0005) and blood group (c2=10.589, df=4, p= O.032). The infected subjects had parasites densities of between 88-250 parasites/µl with a mean parasite density of 126 parasites/µl of blood.Conclusions: The prevalence of malaria parasites among blood donors was 7.5% Blood donors should be routinely screened for malaria parasites and the blood marked negative or positive as the case may be. Recipients of malaria parasites positive blood should be given prophylactic treatment to prevent transfusion related malaria (TRM).

The risk of transfusion transmitted malaria and the need for malaria screening of blood donors in Abuja, Nigeria

Background: Blood transfusion saves life but it is also a major risk factor in the transmission of certain infections such as malaria, which remains a public health problem in tropical and sub-Saharan Africa.Methodology: This study investigated the prevalence of malaria among 550 blood donors aged 18 to 60 years from blood bank units of some selected hospitals in Federal Capital Territory (FCT), Abuja, using gold standard microscopy for malaria parasite detection.Results: Two hundred and fifty two (45.8%) donors were positive for malaria parasites. Replacement donors had higher prevalence rate of malaria compared to voluntary donors. The distribution of infection on the basis of age revealed the highest prevalence rate of malaria among the 20- 29yrs age group. The rate of infection among the males and the females was not significantly different (p>0.05). No association was observed between the blood group types and the rate of malaria infection (p > 0.05).Conclusion: A high prevalence of malaria parasitaemia was observed among blood donors in FCT, Abuja, Nigeria in this study. The introduction of malaria screening as part of routine screening for blood donation and the provision of modern blood screening equipment within healthcare facilities are highly advocated.Keywords: Blood, Malaria, Microscopy, ABO Blood grou

Effect of neem fertilizer rates and weed control methods on the growth and yield of soybeans (Glycine max (L.) merrill) in north Central Nigeria

Two field experiments were conducted at the Research Farm of the Ibrahim Badamasi Babangida University, Lapai, Niger State during the 2018 and 2019 rainy seasons to determine the effect of neem fertilizer rates and weed control methods on the growth and yields of soybeans. The experimental treatments were made up of four neem fertilizer rates (0, 50, 100 and 150 kg ha-1) and six weed control methods (pendimethalin at 1.5 kg a.i ha-1 followed by one hoe weeding, pendimethalin at 2.0 kg a.i. ha-1 followed by diuron at 1.5 kg a.i ha-1, weeding once at 3 WAS, weeding twice at 3 and 6 WAS, weed free and weedy check. The experiment was a 3 × 3 factorial experiment laid out in a Randomize complete block design replicated three times. TGX 1448 – 2E variety of soybean was used for the study. Result showed that weed control efficiency was better with the use of 150 kg ha-1 of neem fertilizer, while decrease in weed dry matter was obtained at 50 kg ha-1. Increase in number of leaves and leaf area were encouraged with 150 kg ha-1 of neem fertilizer. Weed free treatments recorded the highest grain yield and 100 seed weight of soybean. Pendimethalin at 1.5 or 2.0 kg a.i ha-1 supplemented with one hoe weeding or diuron at 1.5 kg a.i ha-1 respectively can be an alternative for better control of weeds to obtain greater yield of soybean in the study area