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Wukari, Nigeria

Oladoja N.A.,Adekunle Ajasin University | Adelagun R.O.A.,Federal University, Wukari | Ahmad A.L.,Universiti Sains Malaysia | Unuabonah E.I.,Redeemers University | Bello H.A.,Adekunle Ajasin University
Colloids and Surfaces B: Biointerfaces

A novel adsorbent, magnetic, macro-reticulated cross-linked chitosan (MRC) was synthesised for the removal of tetracycline (TC) from water using a source of biogenic waste (gastropod shells) as a pore-forming agent. The insertion of crosslinks into the chitosan frame was confirmed by FTIR analysis, while the stability of the MRC was demonstrated via a stability test performed in an acidic solution. The enhanced porosity of the MRC was confirmed by the evaluation of its porosity, a swelling test and the determination of its specific surface area. The time-concentration profile of the sorption of TC onto the MRC demonstrated that equilibrium was attained relatively quickly (120min), and the data obtained fitted a pseudo second order (r2>0.99) kinetic equation better than a pseudo first order or reversible first order kinetic equation. The optimisation of process variables indicated that the sorption of TC onto the MRC was favoured at a low solution pH and that the presence of organics (simulated by the addition of humic acid) negatively impacted the magnitude of TC removal. The area of coverage of TC on the MRC (2.51m2/g) was low compared to the specific surface area of the MRC (47.95m2/g). The value of the calculated energy of adsorption of TC onto the MRC was 100kJ/mol, which is far above the range of 1-16kJ/mol stipulated for physical adsorption. © 2014 Elsevier B.V. Source

Oladoja N.A.,Adekunle Ajasin University | Adelagun R.O.A.,Federal University, Wukari | Ahmad A.L.,Universiti Sains Malaysia | Ololade I.A.,Adekunle Ajasin University
Process Safety and Environmental Protection

In tandem with the quest for the development of sustainable strategies for the recovery of P from P-rich aqua waste streams, thermally treated gastropod shell (GS) was investigated as a reactive material for P-recovery from aquaculture wastewater (AQW). The enhanced defects in the surficial physiognomies, imparted by the thermal treatment process, accounted for the higher P-recovery efficiency. This contradicted the claim that the conversion of the carbonate form of calcium to the oxide form was the reason for the higher P-recovery efficiency of thermally treated calcium rich materials. The fittings of the time-concentration profiles of the P-recovery process to different kinetic models and the determinations of the thermodynamic parameters of the precipitation reaction showed that both adsorption and precipitation were the underlying mechanism of the P-recovery process, using the thermally treated GS. In addition to the removal of P, substantial amount of the total nitrogen in the AQW was also removed. The evaluation of the effects of the P-recovery process on the quality characteristics of the AQW showed that there was significant improvement in the overall physicochemical characteristics. © 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Source

Oladoja N.A.,Adekunle Ajasin University | Adesina A.O.,Adekunle Ajasin University | Adelagun R.O.A.,Federal University, Wukari
Ecological Engineering

Gastropod shell (GS), whose distribution is worldwide and mineralogical assemblage is aragonite, was packed in a glass column and evaluated for phosphate capture and recovery from aqua system. The column reactor was operated in a batch-continuous mode, considered as a close approximation to a practical water treatment system, for 30 days. The time-concentration profile parameters were derived at different influent phosphate concentrations and hydraulic residence time (HRT) to determine the performance efficiency of the reactor column. The mechanism of phosphate removal was investigated and phosphate fractionation protocol was employed to elucidate the form and pattern of phosphate distribution in the spent reactor. Variations in influent phosphate concentration and HRT had minimal influence on the time-concentration profile parameters and the performance efficiency of the column reactor within the process variables studied. The first order rate constant (k1) showed that increase in the HRT of the influent in the SS column reactor does not enhance the phosphate removal. The value of the saturation index (SI) obtained over the 30 days period were all positive and the thermodynamic parameter (δG) was <0 which is an indication of supersaturation, the significant role of precipitation as a mechanism of phosphate removal in the reactor and spontaneity of the precipitation reaction. The order of distribution of each fraction of P, relative to the total phosphorus (T-P) in the phosphate laden SS, is as follows: dicalcium phosphate (Ca2-P) (42.5%)>ten-calcium phosphate (Ca10-P) (40.50%)>octacalcium phosphate (Ca8-P) (16.65%)>occluded phosphate (O-P) (0.35%). The simple appraisal of the fertilizer value of the spent reactor showed that it would preferentially serve as a soil conditioner cum fertilizer in acidic soil. © 2014 Elsevier B.V. Source

The trade liberalization processes of the Economic Community of West African States (ECOWAS) are implemented through such interventions like free international trade, common external tariff wall, the consolidation or freezing of custom duties and non-tariff barriers to the intra-trade among others. However, the extent to which these efforts have translated to the intra-industry trade in the prepared foodstuff products has not been investigated yet. The objectives of this study are to assess the intra-industry trade theory in cereal and miscellaneous edible preparations; to evaluate the growth rates of simultaneous exports and imports in these prepared foodstuff sub-sections; to evaluate the extent of the intra-industry trade in the sub sections, and to determine the effects of the Nigeria's and partners' characteristics on the intra-industry trade. The results revealed that the intra-industry trade in cereal preparations are positively and significantly influenced by the partners' gross national income (GNI) per capita and the partners' foreign direct investment (FDI), but they are negatively influenced by the Nigeria's household final consumption expenditure. Also, the intra-industry trade in miscellaneous edible preparations is influenced positively by the partners' GNI per capita and the partners' households' final consumption expenditures, while the Nigeria's foreign direct investment and the value added by manufacturing negatively influence the intra-industry trade in the product sub-sections within the ECOWAS sub-region. Both exports and imports growth rates of these products fluctuate, but more in the imports of miscellaneous edible preparations. Cost saving options in transportation, the use of efficient machines during the production, processing and packaging are recommended. Source

Al-Betar M.A.,Al - Balqa Applied University | Awadallah M.A.,University of Palestine | Khader A.T.,Universiti Sains Malaysia | Bolaji A.L.,Federal University, Wukari
Applied Soft Computing Journal

This paper proposes a tournament-based harmony search (THS) algorithm for economic load dispatch (ELD) problem. The THS is an efficient modified version of the harmony search (HS) algorithm where the random selection process in the memory consideration operator is replaced by the tournament selection process to activate the natural selection of the survival-of-the-fittest principle and thus improve the convergence properties of HS. The performance THS is evaluated with ELD problem using five different test systems: 3-units generator system; two versions of 13-units generator system; 40-units generator system; and large-scaled 80-units generator system. The effect of tournament size (t) on the performance of THS is studied. A comparative evaluation between THS and other existing methods reported in the literature are carried out. The simulation results show that the THS algorithm is capable of achieving better quality solutions than many of the well-popular optimization methods. © 2016 Elsevier B.V. All rights reserved. Source

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