Md. Sakinul Islam

Fabrication of phosphate microcrystalline rice husk based cellulose particles and their electrorheological response

As a dry-based electrorheological (ER) material, phosphate microcrystalline cellulose (MCC), which exhibits ER properties under anhydrous conditions, was fabricated by the phosphorylation of MCC particles. The MCC particles were initially synthesized by the three step preparation of an alkali treatment, bleaching, and hydrolysis of cellulose particles from rice husk. The phosphate MCC was then synthesized via the phosphoric ester reaction of urea with phosphoric acid and MCC, and its chemical characteristics were examined by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The phosphate MCC particles were dispersed in silicone oil to produce an ER fluid (10vol%), and its chain structure was observed directly by optical microscopy. The rheological behavior of the ER fluid was tested using a rotational rheometer under a range of electric fields, showing a polarization mechanism with a slope of 2.0 for the yield stress as a function of the applied electric field strengths.

Electrochemically active carbon nanotube (CNT) membrane filter for desalination and water purification

Abstract Recently, extraordinary breakthroughs have been made toward applying nanostructured materials such as carbon nanotubes (CNTs), porous graphene membranes in water purification, and desalination applications. In this regard, the potential of the electrochemically active CNT membrane has been highly strengthened for the last few decades. One of the main advantages of such approach is the capability of CNT channel to permit the water flow easily. The perusal of the literature showed that the performance of CNT-based membrane can be three times higher than that of the conventional membrane devices. The unique and excellent characteristics of CNT membrane can outperform the conventional polymer membranes. The CNT membrane has been widely used to adsorb chemical and biological contaminants as well as ion separation from seawater due to their high stability, great flexibility, and large specific surface area. Electrochemically active CNT filters deliver further electrooxidation of the adsorbed contaminants. Usually, polymeric membranes have flexible chains for which it fails to have well-defined pores necessary for filtration. On the contrary, CNT-based filters can provide pores with appropriate sizes and configurations by tailoring the growth parameters. The narrow pores of CNTs are capable of filtering water while eliminating ions (Na+/Cl−). Even this type of membrane is capable of removing bacteria from water and heavy hydrocarbon from petroleum. However, the success of desalination entirely depends on the basic design of the CNT-based filter with detailed optimization of the process parameters. Polymer filters cannot be recurrently used through several cycles since the elimination of fouling ingredients is difficult. Even though electrochemically active CNT-based membranes have lot of advantages due to their hydrophobic nature, high porosity and specific area; there are numerous traits, which are yet to be considered and optimized. Thus, the intrinsic properties of CNT and the fabrication of the membrane could be critical factors for their applicability in various water treatment processes. This chapter provides an explicit and systematic overview of the recent progress of electrochemically active CNT membranes addressing the current prevalent problems associated with water treatment and desalination. The physiochemical aspect including the working principles of this type of membrane have been discussed. The prevailing challenges and future perceptions are also discussed.

Optimization and modelling of delignification process for nanocrystalline cellulose production from rice husk biomass

Nanocrystalline cellulose (NCC) has been attributed as a noble material due to its superior properties for miscellaneous applications in medical science, pharmaceutical production and engineering fields. The major problems associated with the production of NCC are low production rate and inefficient process. Alkaline delignification plays an important role for the mass production of NCC from lignocellulosic biomass. In order to fulfil these research gaps a fractal kinetic model of alkaline delignification of rice husk biomass (RHB) was studied with process optimization. Fifteen kinetic experiments of alkaline delignification for NCC production from RHB, as designed by the Minitab® 2014b software using the Box-Behnken method, were performed in a 2L jacketed glass reactor under three process parameters (time, temperature and alkali concentration) with ranges of 2-10 hours, 40-100°C and 1-4M, respectively. The nucleic growth model of fractal kinetics, developed by Nguyen & Dang (2007), has been successfully ...