Statistical modeling and mix design optimization of fly ash based engineered geopolymer composite using response surface methodology

© 2018. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Fly ash-based geopolymer binders have been identified as one of the alternatives to the Ordinary Portland Cement (OPC), which qualify the criteria of green construction material. In the process of enhancement of the properties of geopolymer; engineered geopolymer composite (EGC) is a recent development that is classified as the high-performance fiber reinforced geopolymer matrix. The philosophy of the development of EGC is to achieve high compressive strength and ductility. In this paper, statistical models are developed to predict the mechanical and post-cracking properties of EGC using Response Surface Methodology (RSM). In this regard, effects of three principal variables; molarity of sodium hydroxide, sodium silicate to sodium hydroxide ratio, and curing temperature on the properties of fresh and hardened EGC (setting time, compressive strength, elastic modulus, flexural strength, flexural toughness, ductility index, tensile strength, tensile first crack strength and tensile strain capacity) were investigated. All models are found significant because, and the difference between predicted R2 and adjustable R2 was found less than 0.2. The optimized mixture proportion was assessed using multi-objective optimization technique as discussed in the RSM literature. Finally, an experimental program was performed to validate the optimized mixture proportion. The predicted and experimental results were found in a close agreement because the variation between the predicted and the experimental results was obtained less than 5%. The proposed method can be performed for any objective value of the EGC property with desirability almost equal to one, improving the yield, the reliability of the product and the processes.Peer ReviewedPostprint (author's final draft

Nickel Removal By Adsorption Using Oil Palm Fibre.

Nickel (Ni) is present in waste waters of a number of industries e.g. steel, electroplating, batteries manufacture, etc. Conventional heavy metal removal technologies such as ion exchange, chemical precipitation, reverse osmosis, etc. are often ineffective or expensive

Low Cost Removal Of Disperse Dyes From Aqueous Solution Using Palm Ash.

Palm oil and textile industries are important contributors to Malaysia's economic growth. However, these industries also generate various pollutants of the environment. This research explores the possibility using a low cost adsorbent i.e. ash produced from palm oil factory, for the removal of dyes from aqueous solution

Statistical modeling and mix design optimization of fly ash based engineered geopolymer composite using response surface methodology

© 2018. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Fly ash-based geopolymer binders have been identified as one of the alternatives to the Ordinary Portland Cement (OPC), which qualify the criteria of green construction material. In the process of enhancement of the properties of geopolymer; engineered geopolymer composite (EGC) is a recent development that is classified as the high-performance fiber reinforced geopolymer matrix. The philosophy of the development of EGC is to achieve high compressive strength and ductility. In this paper, statistical models are developed to predict the mechanical and post-cracking properties of EGC using Response Surface Methodology (RSM). In this regard, effects of three principal variables; molarity of sodium hydroxide, sodium silicate to sodium hydroxide ratio, and curing temperature on the properties of fresh and hardened EGC (setting time, compressive strength, elastic modulus, flexural strength, flexural toughness, ductility index, tensile strength, tensile first crack strength and tensile strain capacity) were investigated. All models are found significant because, and the difference between predicted R2 and adjustable R2 was found less than 0.2. The optimized mixture proportion was assessed using multi-objective optimization technique as discussed in the RSM literature. Finally, an experimental program was performed to validate the optimized mixture proportion. The predicted and experimental results were found in a close agreement because the variation between the predicted and the experimental results was obtained less than 5%. The proposed method can be performed for any objective value of the EGC property with desirability almost equal to one, improving the yield, the reliability of the product and the processes.Peer Reviewe

Palm oil mill effluent digestion in an up-flow anaerobic sludge fixed film bioreactor

Theeffectoforganic loadingrate (OLR) providedby hydraulic retention time(HRT) and influent chemical oxygen demand (CODin) on the performance of an up-flow anaerobic sludge fixed film (UASFF) bioreactor treating palm oil mill effluent (POME) was studied. Anaerobic digestion of POME was modeled and analyzed with two variables i.e. HRT and CODin. Experiments were conducted based on a general factorial design and analyzed using response surface methodology (RSM). The region of exploration for digestion of POME was taken as the area enclosed by HRT (1 to 6 days) and CODin (5260 to 34725 mg/L) boundaries. A simultaneous increase of the variables determined a decrease of COD removal efficiency, SRT and SRF and an increase of COD removal rate, VFA/Alk., CO2 fraction in biogas, methane production rate. The best COD removal rate for POME treatment in an anaerobic hybrid reactor has obtained at an OLR of 17.6 g COD/l.d while it was at 26.21 g COD/l.d (Corresponds to CODin of 26210 mg COD/l and HRT of 1 day) in the present study. Minimum and maximum SRT values obtained were 16 and 1904 days at OLR of 34.73 and 0.88 g COD/l.d, respectively. The present study provides valuable information about interrelations of quality and process parameters at different values of the operating variables

Performance of a Powdered Activated Carbon (PAC) Augmented Activated Sludge Process Treating Semi-Aerobic Leachate

Semi-aerobic leachate is characterized by organic matter (COD, BOD) which is relatively low in concentration and difficult to biodegrade. In conventional treatment systems, the low biodegradability is attributed to partial stabilization of leachate at the landfill. Biological treatment of leachate in Malaysia is not well established and any important data for the treatment process is not available. The behavior of microbes is unknown for semi aerobic leachate. This research was conducted to establish some of the important data in the biological treatment of semi-aerobic leachate with and without the influence of powdered activated carbon (PAC). For the present study, semi aerobic leachate was collected from Pulau Burung Landfill Site (PBLS), Nibong Tebal, Penang, Malaysia. The experiment involved operating two 16 L laboratory-scale activated sludge reactors in parallel at room temperature and adjusted to pH of 6.5±0.5. One of the reactors was supplemented with powdered activated carbon (PAC) of 75-150 μm size to observe its effect on leachate biodegradation. The results showed enhanced reactor performance due to PAC addition COD, NH4- N, NO3-N, TKN, BOD and colour removals was higher