Chemical Engineering

The importance of controlling water pollution has increasing in recent years. Dyes are visible in nature, despite it constitutes only a small portion of water pollution to the environment. Color delivery onto the textile fibres in the form of dyes is not an efficient process. As a result, most of the textile industry wastewater is coloured. The treatment to remove this color was not considered until the usage of synthetic dyes. Due to the effects caused by the synthetic dyes to the environment. Government is forcing textile industries to treat their waste effluent to an increasingly high standard before releasing it to the environment due to the recalcitrant nature of modern synthetic dyes. Several strategies have been investigated cost-effective process to remove the colour from wastewater produced by the textile industry. This article reviews the current available technologies and suggests an effective, cheaper alternative for dye removal and decolourisation applicable on large scale.

Rice husk, agricultural waste material of environmental  impact,  was carbonized at temperatures of 300 - 600⁰C in an oven for 2h, after which its adsorption capacities was investigated for the adsorption of acenaphthene in synthetic aqueous solution, at increasing concentrations (50–150mg/L). The yields of carbon obtained from the raw rice husk ranged from 20 - 40 % (w/w), while the adsorption capacities of rice husk increased with increasing carbonization temperature and increasing initial concentration of acenaphthene. The removal efficiencies of the rice husk increased from 71.37 - 80.56% as the carbonization temperature increased from 300 - 600⁰C, but decreased with increasing initial concentration of acenaphthene. The adsorption equilibrium data obtained, fitted well to the Freundlich, Langmuir, Temkin and Dubnin-Radushkevich isotherms with minimum correlation values of 0.9981, 0.9262, 0.9667 and 0.9215, respectively, although, generally decreases with increasing carbonization temperature. The error analysis showed the order of suitability of the isotherm models selected to be Temkin > Freundlich > Dubnin-Radushkevich > Langmuir. This study shows that carbons rice husk possesses high potency of being used as activated carbon for the removal of acenaphthene from wastewater.

The degradation of Poly(ethylene terephthalate) and polystyrene foam waste could be accelerated using microbes. The aim of the study was to determine the degree of biodegradation of poly(ethylene terephthalate) films and Polystyrene foam by Fourier transform infrared (FTIR) spectroscopy. Further, chemical changes like formation of ester group was observed in PET powder when buried in soil under laboratory conditions. C = C bond stretching in PET powder inoculated in soil, sewage and cowdung was evident in this study. On inoculation of PET flakes in soil, sewage and cowdung, FTIR spectral analysis reveal C-H and C=C bond stretching. Except in PET flakes in cowdung , PET inoculation in soil and sewage elicited C=O bond stretching. PS powder inoculated in soil, sewage and cowdung underwent degradation which in reflected in the FTIR spectral analysis (C-O, bond stretching). Furthermore, PS powder on inoculation with sewage elicited C-H and C=C bond stretching, while in cowdung it resulted in O-H, C=O and C=C bond stretching. PS flakes when buried in soil, sewage and cowdung exhibited C=C bond stretching. In addition, O-H, C-H, C=O bond stretching was evident in PS flakes buried in cowdung. Thus fungal species (Aspergillus sp., Penicillium sp. and Fusarium sp) could be used as a biological agents to degrade PET and PS foam.

The object of the present paper is to give generalized relationships of space-times, for two different ordered reactions (order ?0, 1) occurring in a steady-state plug flow reactor, for special case of complete conversion. It is shown how the Hypergeometric function can be used in case of complete conversion; which in turn is related to Gauss’s pi function , given in literature [3], [4]. Several cases of working techniques with these relationships are also indicated briefly.

The failures of the bituminous pavements are not only due to increase in traffic but also due to extreme climatic conditions prevailing in the country. The addition of sulphur to the bitumen can improve the quality of bitumen and enhance its properties as far as its use in the road construction is considered. In this paper the effect of addition of sulphur on the physical properties of the bitumen is studied and the optimum dose of sulphur to be added to the bitumen is also determined. The effect of Aging on the physical properties of Sulphur modified bitumen is also discussed in this paper.

A study on electro less plated yarn charactertics through Box Behnken Design by various the sliver nitrate amount, temperature and time has been reported. The cotton and polyester yarns were plated with sliver nitrate by electroless plating at various concentration, temperature and time. The surface morphology, antimicrobial activity, electrical conductivity, strength and elongation have been measured for cotton and polyester silver plated yarn. It is observed from SEM image that deposition and firm attachment of sliver particle over the surface of yarn structure. It is also observed that the sliver plated yarns have better antimicrobial activity, electrical conductivity and strength than normal yarn.

A fluidized bed reactor with a perforated draft tube was employed to obtain hydrodynamic data for different Geldart’s particle group A, B, C & D by using various operating condition. The stability and hydrodynamics properties of a fluidized bed are determined primarily with respect to minimum fluidization velocity, pressure drop, minimum bubbling velocity, fluidization quality with a perforated draft tube by changing the total gas flow rate through the column. The result of calculation showed that, the pressure drop through the column increases with the increase in gas flow rate. At about 1.7 Ums some bed instability was observed which is characterized by fluctuation in pressure drop, with increase in gas flow rate this phenomenon disappeared. The effects of perforated draft tube on fluidization can be evaluated by comparing the experimental results by using the Geldart’s correlation with the correlation derived. Moreover the various correlations are derived by using the multiple regression analysis method (Polynomial method) for fluidized bed with perforated draft tube.

The potential use of Aleppo pine (Pinus halepensis Mill.), a lignocellulosic-based fiber found in discontinuous bands along the Mediterranean Basin, for the removal of a basic cationic dye: Methylene blue (MB) was investigated by adsorption in batch mode. In order to investigate the mechanism of dye sorption and potential rate controlling steps, pseudo first-order, pseudo second-order and intra-particle diffusion models equations have been used to test experimental data. Kinetic analysis of models has been carried out for initial MB dye concentration in the range of 20-100 mg/L. The rate constants models have been determined and the correlation coefficients have been calculated in order to assess which model provides the best fit predicted data with experimental results. The results showed that pseudo second-order equations model provide the best fit to experimental data for different initial MB dye concentrations implying that chemisorption mechanism may play an important role for the adsorption of dye onto Aleppo pine fibers. The results indicate also that Aleppo pine fibers adsorb Methylene blue efficiently and could be employed as a low-cost alternative in textile wastewater treatment for the removal of cationic dyes.

A teacher in an engineering college is a professional in two ways, he is an engineer and he is also a teacher. Teacher has to keep on upgrading himself in his subject and at the same time has to develop skill to translate his expertise in his field into a proper style of teaching leading to effective learning by the students. The present communication is aimed at stimulating the teacher to think, evolve and execute practice leading to effective learning by the students. Here the author presents his personal experience on some of the effective teaching techniques in teaching various subjects of Chemical Engineering at undergraduate level. Details of the methods are also given.

Following the large reserve of untapped natural gas in the world, the utilisation of gas reserve is a possible solution to increasing energy demand and a possible reduction in pollution and crude oil dependency. Due to its (Natural gas) lower hydrocarbon fraction it can be converted to higher petroleum products such as petrol (synthetic fuel), diesel, naphtha and aviation kerosene which are products on high demand. Emission performances of hydrocarbon products produce from gas are better than those from conventional crude oil cracking process. A process known as Fischer Tropsch (F-T) process, requiring an F-T plant is used for the conversion of natural gas into higher derivatives. The process involves three basic stages; Syngas Generation, Catalytic Synthesis to form petroleum products and Hydro-processing to convert into finished product. In an attempt to ensure a major step in utilising the large gas reserve in Nigeria, the setup of F-T plant in the Niger-Delta region is proposed. The choice of establishing the F-T plant in the Niger-Delta region is not political but an economic one; this is so because the feedstock (natural gas) is available in large quantity and transportation is less, thereby cutting cost. Investors will require reasonable model variables which includes a suitable depreciation evaluation, a profitable risk portfolio and a project fixed cost, which are the responsibilities of a petroleum economist. This paper addressed a comparative study of Gas to liquid fuel as an alternative to refined crude oil. Various parameters were evaluated: physical and chemical properties of the product, emission discharge, pollutants. The results obtained showed that gas to liquid products has environmental and efficient benefits over petroleum derived products (crude oil).