Nik Meriam Nik Sulaiman

A Packed Bed Membrane Reactor for Production of Biodiesel Using Activated Carbon Supported Catalyst

In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor.

Continuous adsorption of lead ions in a column packed with palm shell activated carbon

The continuous adsorption of lead ions from aqueous solution on commercial, granular, unpretreated palm shell activated carbon (PSAC) was studied. Effect of pH, flow rates and presence of complexing agents (malonic and boric acids) were examined. The breakthrough period was longer at pH 5 indicating higher adsorption capacity of lead ions at higher pH. Increase of the flow rate, expectedly, resulted in the faster saturation of the carbon bed. Presence of complexing agents did not improve adsorption uptake of lead ions. However, presence of malonic acid resulted in smoother pH stabilization of solution compared to single lead and lead with boric acid systems. The results on continuous adsorption of lead were applied to the model proposed by Wang et al. [Y.-H. Wang, S.-H. Lin, R.-S. Juang, Removal of heavy metals ions from aqueous solutions using various low-cost adsorbents, J. Hazard. Mater. B 102 (2003) 291-302]. The agreement between experimental and modelled breakthrough curves was satisfactory at both pHs.

Application of TOPSIS and VIKOR improved versions in a multi criteria decision analysis to develop an optimized municipal solid waste management model

Selecting a suitable Multi Criteria Decision Making (MCDM) method is a crucial stage to establish a Solid Waste Management (SWM) system. Main objective of the current study is to demonstrate and evaluate a proposed method using Multiple Criteria Decision Making methods (MCDM). An improved version of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) applied to obtain the best municipal solid waste management method by comparing and ranking the scenarios. Applying this method in order to rank treatment methods is introduced as one contribution of the study. Besides, Viekriterijumsko Kompromisno Rangiranje (VIKOR) compromise solution method applied for sensitivity analyses. The proposed method can assist urban decision makers in prioritizing and selecting an optimized Municipal Solid Waste (MSW) treatment system. Besides, a logical and systematic scientific method was proposed to guide an appropriate decision-making. A modified TOPSIS methodology as a superior to existing methods for first time was applied for MSW problems. Applying this method in order to rank treatment methods is introduced as one contribution of the study. Next, 11 scenarios of MSW treatment methods are defined and compared environmentally and economically based on the waste management conditions. Results show that integrating a sanitary landfill (18.1%), RDF (3.1%), composting (2%), anaerobic digestion (40.4%), and recycling (36.4%) was an optimized model of integrated waste management. An applied decision-making structure provides the opportunity for optimum decision-making. Therefore, the mix of recycling and anaerobic digestion and a sanitary landfill with Electricity Production (EP) are the preferred options for MSW management.

Limiting permeate flux in the clarification of untreated starfruit juice by membrane ultrafiltration

Abstract This paper describes the limiting flux of untreated starfruit juice obtained during clarification using membrane ultrafiltration. Experiments were conducted in a stirred cell unit using membranes of 25,000 MWCO at 30°C for a range of juice concentration varying from 0.46 to 6.5 wt.%. In addition to the limiting flux behaviour, he relationship between the concentration of solute in the bulk solution and the gel layer was also established. The measured experimental data was analysed using the gel model. In general, it was concluded that the gel model could not satisfactorily describe the clarification of starfruit juice. The observed deviation from the model was mainly due to the high pectin content of the juice.

Prediction of dynamic permeate flux during cross-flow ultrafiltration of polyethylene glycol using concentration polarization-gel layer model

Abstract A tubular ultrafiltration model which couples the formation of a cake layer on the membrane surface and the presence of a polarized layer above the cake has been developed, which contains a single constant and the cake layer resistance to be evaluated from experiments. In the model, the tangential flow of feed material is assumed to induce a shearing effect on the cake layer resulting in the re-entrainment the particles into the bulk stream. The validity of the model over a range of cross-flow velocity, transmembrane pressure (TMP) and solute concentration was confirmed using experimental permeate fluxes obtained from the ultrafiltration of polyethylene glycol. Excellent prediction is observed for solute concentrations above some critical value at which a well developed cake layer is believed to have been formed. For concentrations below this value, the model under predicted the steady-state permeate fluxes. By ignoring the presence of the polarized layer, the model always over predict the dynamic fluxes.

The Occurrence of Haze in Malaysia: A Case Study in an Urban Industrial Area

Abstract — Klang Valley, a heavily industrialized urban area in Malaysia, has experienced severe haze episodes since the early 1980s. Total Suspended Particulate matter (TSP) is used in studying this phenomenon. Three severe haze episodes during the early 1990s are reviewed; August 1990, October 1991, and August–October 1994. The nature of these episodes, their possible causes, and their major features are discussed. Meteorological conditions associated with these episodes were analyzed. Results of the study indicate that stability and trapping of particles are the main factors affecting the pollution during haze periods. Maximum total suspended matter (TSP) was recorded in October 1991. The August–October 1994 episode was the most persistent and least affected by meteorological variables. Analysis of wind direction data showed that southerly and southwesterly winds coincided with the worst haze periods.

Synthetic reactive dye wastewater treatment by using nano-membrane filtration

AbstractThe batik industry is considered to be one of the largest textile cottage industries in the Southeast Asian region. Batik processing utilizes wax as a physical resistant and consumes a large amount of water during dyeing, fixing, and washing process; thus, generating harmful wastewater including dye, wax, and other auxiliaries. Respectively, an efficient wastewater treatment method is deemed necessary to meet legal emission standards. In this study, application of polyamide nano-membrane to remove dyes was evaluated for five different fiber reactive dyes’ wastewater, namely reactive blue 15, reactive red 194, reactive yellow 145, reactive black 5, and reactive orange 16. The discussed dyes were tested in low concentration (16 mg/l) during a 60 min filtration process. The efficiency of filtration was calculated based on pre-process and post-process analytical experiments. The flux for all the samples ranged between 7.8 and 9.2 ml/cm2 s. The permeate pH value of the samples was observed to slightly ...

A systematic assessment method for the investigation of the PVDF membrane stability

AbstractThis article reports the systematic assessment method for membrane stability using a hydrophilic polyvinylidene fluoride (PVDF) membrane. In this study, bovine serum albumin, fouled PVDF flat-sheet membranes were cleaned with sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl). The effects of repeated chemical cleaning on membrane water flux recovery and the PVDF membrane intrinsic properties were investigated. The virgin and cleaned membranes were characterised by water flux measurement, field emission scanning electron microscopy, tensile test, Fourier transform infrared, contact angle measurement and protein rejection performance. As expected, higher cleaning efficiency was achieved when using higher concentration and extended cleaning time with NaOCl showing better performance compared to NaOH. It was found that the use of chemical cleaning agent for fouling control has an impact on membrane integrity and shortens their lifespan. Their declining functionality is normally associated with ag...

Membrane Bioreactor for the treatment of natural rubber wastewater

A membrane bioreactor was set up using two pieces of Kubota flat sheet membranes, with nominal pore size of 0.4 ∝m and a total effective area of 0.2 m²atex concentrate processing factory. A steady-state MLSS concentration was attained at 8500 mg/L during biomass acclimatisation. A critical flux of 0.01224 m³/m²h was determined using the flux step method, whereas an optimum operating flux for fouling minimisation was determined from the sub-critical flux region, to be 0.009 m³/m²h at a COD loading of 3500 mg/L. The BOD3 and COD removal efficiencies were 96.78% and 96.99%, respectively.

Factors that Contribute to the Generation of Construction Waste at Sites

Construction industry in Malaysia is growing rapidly with high demand due to vast development and urbanization. Therefore, many commercial and residential buildings are being developed. The increasing number of construction projects in Malaysia will indirectly contribute to the increase of construction waste generation. Thus, waste minimization is an important area of concern in the implementation of the construction waste management in the construction industry of Malaysia. Data collection and observations was conducted at three construction sites which adopt different type of method with different type of building and size of project in Klang Valley. The calculation of the construction waste index generated at these sites is adopted from Poon et al., (2001). Result showed that construction method, size of projects (GFA), type of building, storage method system, human error and technical problem can affect the amount of waste index (debris) and amount of wastage level generated at construction sites. Therefore waste index and wastage level can be used as operational an indicator for waste minimization of the construction activities.