Raphael Iwar - Academia.edu (original) (raw)

Papers by Raphael Iwar

Environmental chemistry and ecotoxicology, 2021

In this study a novel activated carbon derived from Raffia palm shells was synthesized firstly by... more In this study a novel activated carbon derived from Raffia palm shells was synthesized firstly by activating the precursor with phosphoric acid to produce Raffia Palm Shell Activated Carbon (RPSAC) and further functionalized by coating its surface with aluminium hydroxide to produce a composite called Aluminium Oxide-coated Raffia Palm Shell Activated Carbon (ACRPSAC). These adsorbents were extensively characterized and tested for fluoride adsorption in aqueous media using batch adsorption experiment in comparison with a commercially available activated carbon (CAC). ACRPSAC demonstrated excellent qualities and fluoride adsorption capacity as compared to RPSAC. SEM/EDX revealed that ACRPSAC developed both micro and meso-pores on its surface with BET-surface area and pore volume of 715.80 m 2 /g and 0.47 cm 3 /g respectively. FTIR and XRD proved that ACRPSAC was largely amorphous and had sufficient functionality for fluoride uptake in solution. Batch adsorption studies showed that the fluoride removal abilities were in the order of ACRPSAC > RPSAC > CAC with maximum Langmuir adsorption capacity of 4.10 > 2.26 > 2.24 mg/g. respectively. The experimental data was well described by the Langmuir (R 2 = 0.8802-0.9751) and the pseudo-second order kinetic (R 2 = 0.9974-0.9999) models, signifying that fluoride uptake by the adsorbents was a chemisorption process. Thermodynamic studies revealed that the process was spontaneous, endothermic and feasible for ACRPSAC and RPSAC but was non-spontaneous for CAC. It was concluded that ACRPSAC is an excellent activated carbon for eliminating fluoride from groundwater and can be further studied for its commercialization.

Journal of Engineering Research and Reports, 2021

The present study assessed water quality parameters and attempts to compare four different Water ... more The present study assessed water quality parameters and attempts to compare four different Water Quality Indexes (WQIs) for consistency, similarity and reliability in assessing the water quality of river Benue -an inland river- under wet and dry seasons. The results demonstrate that River Benue is continually being polluted in both dry and wet seasons by different sources, particularly domestic sewage and storm runoffs from farmlands. The quality of the water generally exceeded physiochemical and microbiological infection risk limits recommended in water quality guidelines concerning their use for domestic, recreational and irrigational purposes. Proper sewage treatment and river quality monitoring are needed to guard against hazards to public health and vulnerable river water resources. The WQIs applied were: CCME WQI, BC WQI, Dinius’ WQI and Weighted Arithmetic WQI. To evaluate the differences between these indexes, data on ten water quality parameters (Temperature, pH, total diss...

Journal of Research in Forestry, Wildlife and Environment, 2019

This study examined the type and abundance of Ecto and Endo parasites of Nile rat ( Arvicanthis n... more This study examined the type and abundance of Ecto and Endo parasites of Nile rat ( Arvicanthis niloticus ) in rural areas of Benue State. A total of 400 rats (average of 100 for each location) were systematically captured from the wild in four locations namely, Makurdi, Gwer West, Guma and Kwande Local Government Areas (L.G.A) of Benue State for the entire studies on the captive rearing of Nile rats. However, only 10 % of the captured rats from each location were subjected to parasite isolation procedures in accordance with standard methods. The number of each parasite isolated and identified from each location were recorded and documented as findings of the study. Results revealed that four ecto parasites (Lice,Termite, Soft Tick and Hard Tick) were prevalent in all the locations considered. Similarly, three endo parasites (Hook Worm, Tape Worm and Myosis) were isolated from the rats in all locations. In general Lice (17%) and Tick (13%) were observed to be dominant ecto parasite ...

Journal of environment and earth science, 2016

This study was carried out to evaluate the particle size distributions and erodibility indices at... more This study was carried out to evaluate the particle size distributions and erodibility indices at two soil depth ranges, 0 – 60 cm and 60 – 90 cm, of the three geological sediments underlying 100% of the landscape of the Idah-Ankpa Plateau of the Anambra Basin, Nigeria. The aim was to explain why the three geological sediments, namely, the Upper Coal Measures (UCM, 36%), the Ajalli Sandstones (AS, 44%) and the Lower Coal Measures (LCM, 20%) are exposed to varying degrees of vulnerability to gully (soil) erosion. The depth range 0 – 60 cm was considered the topsoil most prone to rill erosion, the range 60 – 90 cm (and above) was the subsoil, the normal depth of a formed gully. The particle size distributions were determined by the hydrometer method plus NAOH for dispersion, and the erodibility indices were computed in decimal units using the clay ratio method. Data were analyzed using descriptive statistics. In the top and subsoils, the LCM was observed to have the highest mean ...

Civil and environmental research, 2014

This research investigates the various sources of water available in Makurdi metropolis, the stat... more This research investigates the various sources of water available in Makurdi metropolis, the state capital of Benue State, Its distribution across the various wards, its availability and frequency using both primary and secondary sources of data. A total of 200 respondents (households) were chosen randomly across the various wards of Makurdi. The questionnaire was administered to 200 households, 193 returned the questionnaires while 7 of them were lost. The results of the analysis show that 53.7% of all the respondents had running public taps in their homes while 46.3% do not have such facilities at home and of those that had running taps at home indicates that only 23.8% of them had water running more than three times in a week. Also about 45.4% of the respondents only had water occasionally and 18.8% had water once a week. The remaining 15% had water running in their taps two to three times in a week. More so, this study here shows how sufficient and adequate is water supply from ...

American Journal of Environmental Protection, 2016

In this study, physically, chemically and biologically pre-treated effluents from a brewery were ... more In this study, physically, chemically and biologically pre-treated effluents from a brewery were characterized for a period of six months. This was to ascertain the type and concentrations of residual pollutants in the effluent streams released to a receiving perennial river in the study area. Effluent samples were collected at the outfall point for a consecutive period of six months, beginning from February, 2014. Samples were preserved and taken to the laboratory for tests on each sampling date. pH and Temperatures (ambient and effluent) were however determined in-situ. All samples were analyzed in accordance with the “standard methods for the examination of water and wastewater”. Pollutants concentrations in mg/l ranged between; 3.25-6.35, 76.4-183.0, 220.0-435.0, 55.1-85.0, 169.4-232.5, 4.70-6.6, 6.05-8.2 and 1.3-4.05 for DO, BOD5, COD, TSS, TDS, NO3-, PO4-3 and NH4+ respectively. Conductivity ranged between 307.0-405.5µs/cm, turbidity was between 24.2-41.35NTU, pH was 6.2-7.15,...

International Soil and Water Conservation Research

Abstract This study investigated the relationships between the average gully depth and the averag... more Abstract This study investigated the relationships between the average gully depth and the average width on two of the three geological sediments underlying the Ida-Ankpa Plateau of the North Central Nigeria. Gully length (L), average depth (D), and average width (W) were measured on 37 and 5 gully samples formed respectively on the Ajalli Sandstones’ (AS) and the Upper Coal Measures’ (UCM) geological sediments. From these, the average volume (V), average cross sectional area (A), and average form factor (W/D) were computed. These sets of variables (L, D, W, V, A, and W/D), a total of six for each gully, were analysed using correlation analysis and the sample bivariate regression to examine the relationships between D and W on the two geological units. Results show that D correlates poorly, positively, and significantly with W on the highly erodible AS (R = 0.565, P

American Journal of Environmental Sciences, 2009

Journal of Environmental Protection

This study was carried out to evaluate the influence of soil consistency limits and shear strengt... more This study was carried out to evaluate the influence of soil consistency limits and shear strength on the relative proliferation of gullies on three geological sediments, namely: the Upper Coal Measures (UCM), the Ajalli Sandstones (AS), and the Lower Coal Measures (LCM), which has been ranked as AS > UCM > LCM. Soil samples were collected from a depth range of 60-90 cm of sampling pits dug at a selected location on each of these texturally homogenous and unique formations. These were analysed for consistency limits and shear strength using standard methods and procedures. Results showed that the plasticity index (PI) of the UCM (PI UCM) was 24.49%; PI AS , 5.89%; and PI LCM , 44.85%. The shear strength (S) of the UCM (S UCM) was 314.74 KN/m 2 ; S AS , 196.23 KN/m 2 ; and S LCM , 321.72 KN/m 2. The results of the study show that rankings of the respective contributions of these two geotechnical properties to the vulnerability of the sediments to gully (soil) erosion follow the same order of proliferation of gullies on the plateau landscape: AS > UCM > LCM. Hence, consistency limits and shear strength parameters partly influence and explain the relative proliferation of gullies on the three formations. Further studies are required to determine other soil factors of gully erosion in the area in order to evolve appropriate management strategies for these sediments.

Applied Water Science

In this work, the quality of River Benue water at Makurdi was assessed for its heavy metal load a... more In this work, the quality of River Benue water at Makurdi was assessed for its heavy metal load alongside seven other physico-chemical parameters using water quality index (WQI) and multivariate statistical tools. A total of 45 samples from three (3) different points along the River course were collected for five months (October 2018–May, 2019) spanning the dry and wet seasons. Samples were analysed in accordance with standard methods. Most of the parameters evaluated were found to fall in the allowable limits of the World Health Organization (WHO) among others, except for colour, turbidity, total suspended solids, nickel, lead and cadmium. WQI analysis using the BISWQI, OWQI and CCMEWQI indicated that all indexing methods were suitable for estimating the WQI of River Benue as they all showed that the water corresponded to the classification as “poor water”. Heavy metal index of the river ranged from13.40–6080.00 and from 47.07–7240.00 for the dry and wet seasons, respectively, and...

The adsorption performance of a packed bed column using zinc chloride modified Raffia Palm Seed A... more The adsorption performance of a packed bed column using zinc chloride modified Raffia Palm Seed Activated Carbon (RPSAC) for the removal of cadmium ion from aqueous solution was investigated. The adsorption kinetics was analyzed using Thomas (KTH), Adam-Bohart (KAB) and Yoon- Nelson (KYN) models. The values of KTH and KAB increased with increasing flow rate and bed height but decreased with increasing initial concentration, while those of KYN were found to increase with increase in flow rate, bed height and initial concentration. The time required for 50% breakthrough for the Yoon-Nelson model decreased with increasing flow rate from 100 to 70 min and increased from 100 to 160 min with increasing bed height, while it decreased from 100 to 40 min with increasing metal ion concentration. In general the kinetics of cadmium adsorption on RPAC was fitted to the models in the order of Thomas > Yoon Nelson > Adam-Bohart with R2 values ranging from 0.71-0.99, 0.73-0.98 and 0.75-0.88 r...

In this study, an appropriate, cost effective and easy to duplicate manually operated biomass bri... more In this study, an appropriate, cost effective and easy to duplicate manually operated biomass briquetting machine suitable for use in rural communities was developed following standard design procedures. Carbonization of the raw material (Raffia Palm Shells) was done using a laboratory muffle furnace. The developed machine was evaluated for the production of charcoal briquettes using the carbonized Raffia Palm fruit shells, a synthetic gum and cassava starch as binders. The qualities of the produced briquettes were measured in terms of the briquette thermal and physical properties following standard methods. Thermal and physical properties of the optimally produced briquettes using the two binder types and those of the convention hard wood charcoal were statistically compared using a one factor Analysis of Variance (ANOVA). The developed briquetting machine had an average throughput capacity of 64kg/hr. Thermal properties of the briquettes and hard wood charcoal ranged from 2.42 – 3...

Reverse osmosis concentrate (ROC) is considered to be an obstacle in the production of high quali... more Reverse osmosis concentrate (ROC) is considered to be an obstacle in the production of high quality water from water reclamation and desalination plants using dense membrane systems. The ROC contaminants include many harmful micro-pollutants and nutrients in addition to the organics recalcitrant to biological treatment, the ROC can pose significant risks to environment and human health if discharged to receiving water environments without proper treatment. The increase in the number of drinking water companies that employ reverse osmosis technology in Makurdi metropolis has necessitated the current study. In this study, reverse ROC from two different sources (groundwater and surface water treatment companies) in Makurdi metropolis-Nigeria was monitored continuously for six months which covered both the rainy and dry season. Standard procedures for sampling and laboratory test were followed in analyzing the ROC samples. The average seasonal values of the tested ROC parameters were co...

In the present study, activated carbons were produced from low-cost agricultural residues and cha... more In the present study, activated carbons were produced from low-cost agricultural residues and characterized. These were; coconut shells carbon (CSC), palm kernel shells carbon (PKC) and a mixture of coconut and palm kernel shells carbon (CCPC). Batch equilibrium experiments were carried out in the laboratory using the adsorbents for the treatment of effluents from a brewery in Makurdi Metropolis, Nigeria. Carbon characteristics ranged between 6.58-7.03%, 0.57-0.65g/cm 3 , 76.0-93.5%, 928.0-1126.0m 2 /g, 23.0-33.7% and 192-303mg/g for ash content, bulk density, iodine sorption, specific surface area, carbon yield and methylene blue number respectively. In the batch equilibrium experiments, pollutants removal efficiency increased with increase in carbon dosage, contact time and pH. The highest removal efficiencies were observed at a dosage of 8g/100ml, contact time of 120minutes and pH of 8 for COD, TSS and TDS as well as for CSC, PKC and CCPC. Comparatively, CSC and CCPC performed be...

Environmental Monitoring and Assessment

Environmental Chemistry and Ecotoxicology

Heliyon, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal Materials and Environmental Science, 2020

Abstract Activated carbon was synthesized from Delonix regia pods by impregnation with zinc chlor... more Abstract
Activated carbon was synthesized from Delonix regia pods by impregnation with zinc chloride. The adsorbent characteristics revealed high surface area and porosities. The adsorption of Methylene Blue (MB) from aqueous solution onto Delonix regia Pod Activated Carbon (DRPAC) was investigated under various experimental conditions in Batch mode of operation. Effects of adsorbent dose, pH, temperature, and contact time were studied. The optimum conditions of adsorption were found to be: adsorbent dose of 0.6 g, pH of 7, Temperature of 30 oC and contact time of 40 minutes. At optimum conditions, removal efficiencies (%) were found to be 88.5, 91.2, 96.5, and 100, while adsorption capacity (qe) was 33.3, 34.3, 36.3 and 37.7 mg/g respectively for the parameters studied. Equilibrium isotherm studies revealed that the adsorption was well described by both the Freundlich and Langmuir models with the Freundlich model exhibiting a better fit (R2= 0.9102). Kinetic studies showed that the adsorption rate was better described by the pseudo second order model (R2= 0.999) as compared to the pseudo first order kinetic model (R2 = 0.969). Thermodynamic parameter estimates showed that MB adsorption on DRPAC is spontaneous, endothermic and feasible. Regeneration and stability of the adsorbent up to five adsorption-desorption cycles was also demonstrated with excellent results. It was concluded that, DRPAC an efficient low-cost adsorbent for the removal of MB from industrial wastewater and hence could generally be used in the treatment of wastewater for colour removal.