Muhammad Irfan Khan

Potential biosorbent derived from Calligonum polygonoides for removal of methylene blue dye from aqueous solution.

The ash of C. polygonoides (locally called balanza) was collected from Lakki Marwat, Khyber Pakhtunkhwa, Pakistan, and was utilized as biosorbent for methylene blue (MB) removal from aqueous solution. The ash was used as biosorbent without any physical or chemical treatment. The biosorbent was characterized by using various techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The particle size and surface area were measured using particle size analyzer and Brunauer-Emmett-Teller equation (BET), respectively. The SEM and BET results expressed that the adsorbent has porous nature. Effects of various conditions such as initial concentration of methylene blue (MB), initial pH, contact time, dosage of biosorbent, and stirring rate were also investigated for the adsorption process. The rate of the adsorption of MB on biomass sample was fast, and equilibrium has been achieved within 1 hour. The kinetics of MB adsorption on biosorbent was studied by pseudo-first- and pseudo-second-order kinetic models and the pseudo-second-order has better mathematical fit with correlation coefficient value (R 2) of 0.999. The study revealed that C. polygonoides ash proved to be an effective, alternative, inexpensive, and environmentally benign biosorbent for MB removal from aqueous solution.

Effect of Na/Al and Si/Al Ratios on Adhesion Strength of Geopolymers as Coating Material

In this study fly ash based aluminosilicate coatings were formulated and the effect of the Na/Al, Si/Al ratios, and curing time upon adhesion strength of geopolymeric coating was measured using Elcometer 108. Geopolymer gained their maximum adhesion within first three days. After 3 days curing on 60oC resulted into a maximum adhesion strength of 10MPa at Si/Al=3 and Na/Al=1.0. Micro structural analysis and Infra red spectroscopy was used to study the geopolymerisation process. Surface profile of fly ash particles shown that degree of reactivity has a direct relation with their surface roughness.

A Review on Geopolymers as Emerging Materials for the Adsorption of Heavy Metals and Dyes

The world water resources are contaminated due to discharge of a large number of pollutants from industrial and domestic sources. A variety of a single and multiple units of physical, chemical, and biological processes are employed for pollutants removal from wastewater. Adsorption is the most widely utilized process due to high efficiency, simple procedure and cost effectiveness. This paper reviews the research work carried out on the use of geopolymer materials for the adsorption of heavy metals and dyes. Geopolymers possess good surface properties, heterogeneous microstructure and amorphous structure. The performance of geopolymers in the removal of heavy metals and dyes is reported comparable to other materials. The pseudo-second order kinetics and Langmuir isotherm models mostly fit to the adsorption data suggesting homogeneous distribution of adsorption sites with the formation of monolayer adsorbate on the surface of geopolymers. Adsorption of heavy metals and dyes onto geopolymers is spontaneous, endothermic and entropy driven process. Future research should focus on the enhancement of geopolymer performance, testing on pollutants other than heavy metals and dyes, and verification on real wastewater in continuous operation.

The Impact of Different Polydimethylsiloxane Core Materials on the Properties of Melamine Formaldehyde Microcapsules

Three different functionalized polydimethylsiloxane based probable self-healing materials were encapsulated by oil-in-water emulsion polymerization melamine-formaldehyde (MF) microcapsules for future applications in self-healing composites systems. The diameter and morphology, thermal properties, and structural analysis of the synthesized microcapsules were determined by scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and electron dispersive spectroscopy (EDS). The results showed that nature of core material plays an important role in the morphology and thermal stability of the microcapsules.

Effect of Sonication on the Stability of Nanofluids Based on the Mixture of Kapok Seeds Oil and Multi Walled Carbon Nanotubes

Environmental pollution problem and depletion of petroleum reserves have driven the researchers to use non-edible oils as a low cost feedstock. This work represents the preparation of nano fluids using kapok (ceiba pentandra) seeds oil (KSO) and multi walled carbon nano tubes (MWCNTs). The present study consists of two stages. The first step is the extraction of KSO through Soxhlet extraction using n-hexane as a solvent. The second step is the mixing of extracted oil with carbon nanotubes using sonicator, with different time intervals, to develop nanofluids. The visualization technique was used by capturing photographs to evaluate the stability of the nanofluids. The photographs showed good agreement for the stability of nanofluids for more than 1 week. KSO and prepared nanofluids were characterized by using Fourier transformed infra-red spectroscopy (FTIR) and scanning electron microscopy (SEM).

Quantification of geopolymers production by chemical methods- A short review

Inorganic polymers are the aluminosilicate materials possessing properties superior than ordinary Portland cement. In this review paper the chemical techniques used for determining degree of reaction of fly ash or the quantity of geopolymer material produced have been discussed. These methods determine the amount of product formed in percentages. The methods include HCl method, salicylic acid method, and picric acid method. These methods are not only used for fly ash but they are being used for determining the degree of reactions of metakaolin and other pozzolanic materials. The picric acid is an explosive material and its transportation in high concentration is dangerous. During its use in laboratory there is also the risk of fire associated with it. According to the microscopic analysis results the picric acid attack dissolves small amount of fine unreacted fly ash particles also. The salicylic acid is easily available but the residue from its treatment contains unreacted fly ash particles, hydration ph...