Junaid Saleem

Development and characterization of novel composite membranes for fuel cell applications

In this paper, we report a novel composite electrolyte membrane consisting of a polyethylene substrate and a Nafion ionomer. Polymer Electrolyte Membranes (PEMs) have been gaining increasing attention in the fuel cell industry due to their excellent proton conductivity and among them the Nafion membrane is by far the most widely used membrane electrolyte. However, it suffers from several drawbacks such as high fuel crossover and low mechanical strength, which lower the fuel cell performance and disturb the structural integrity. In order to deal with these problems, we have prepared a pore filling membrane that is composed of a porous substrate and a filling electrolyte. Nafion was used as a filling electrolyte and was impregnated into the pores of the porous substrate made up of ultra-high molecular weight polyethylene (UHMWPE). The UHMWPE backbone serves as a structural support and blocks the fuel crossover while the impregnated Nafion molecules provide the proton conducting path. A porous UHMWPE membrane with a porosity of approximately 66% was prepared, and the Nafion electrolyte was impregnated into the pores so that an NPE (Nafion–polyethylene composite) membrane was formed. Major accomplishments of this work are (a) the membrane is biaxially oriented and has higher tensile strength and modulus especially under wet conditions as well as better electrolyte conductivity because the resistivity in the system is reduced due to the development of a very thin (13 μm) film composite, and (b) the electrolytic membrane is economical because of the utilization of a lesser amount of ionomer. Systematic characterization of both porous polyethylene and the NPE composite has been performed using SEM, EDAX, XRD, XRF, porosity measurement, tensile tests, proton conductivity, and fuel cell performance tests.

3D graphene-based nanostructured materials as sorbents for cleaning oil spills and for the removal of dyes and miscellaneous pollutants present in water

Oil spills over seawater and dye pollutants in water cause economic and environmental damage every year. Among various methods to deal oil spill problems, the use of porous materials has been proven as an effective strategy. In recent years, graphene-based porous sorbents have been synthesized to address the shortcomings associated with conventional sorbents such as their low uptake capacity, slow sorption rate, and non-recyclability. This article reviews the research undertaken to control oil spillage using three-dimensional (3D) graphene-based materials. The use of these materials for removal of dyes and miscellaneous environmental pollutants from water is explored and the application of various multifunctional 3D oil sorbents synthesized by surface modification technique is presented. The future prospects and limitations of these materials as sorbents are also discussed.

Combating oil spill problem using plastic waste

Thermoplastic polymers (such as polypropylene, polyethylene, polyethylene terephthalate (PET) and high density polyethylene (HDPE)) constitute 5-15% of municipal solid waste produced across the world. A huge quantity of plastic waste is disposed of each year and is mostly either discarded in landfills or incinerated. On the other hand, the usage of synthetic polymers as oil sorbents, in particular, polyolefins, including polypropylene (PP), and polyethylene (PE) are the most commonly used oil sorbent materials mainly due to their low cost. However, they possess relatively low oil absorption capacities. In this work, we provide an innovative way to produce a value-added product such as oil-sorbent film with high practical oil uptake values in terms of g/g from waste HDPE bottles for rapid oil spill remedy.

Oil sorbents from plastic wastes and polymers: A review

A large volume of the waste produced across the world is composed of polymers from plastic wastes such as polyethylene (HDPE or LDPE), polypropylene (PP), and polyethylene terephthalate (PET) amongst others. For years, environmentalists have been looking for various ways to overcome the problems of such large quantities of plastic wastes being disposed of into landfill sites. On the other hand, the usage of synthetic polymers as oil sorbents in particular, polyolefins, including polypropylene (PP) and polyethylene (PE) have been reported. In recent years, the idea of using plastic wastes as the feed for the production of oil sorbents has gained momentum. However, the studies undertaking such feasibility are rather scattered. This review paper is the first of its kind reporting, compiling and reviewing these various processes. The production of an oil sorbent from plastic wastes is being seen to be satisfactorily achievable through a variety of methods Nevertheless, much work needs to be done regarding further investigation of the numerous parameters influencing production yields and sorbent qualities. For example, differences in results are seen due to varying operating conditions, experimental setups, and virgin or waste plastics being used as feeds. The field of producing oil sorbents from plastic wastes is still very open for further research, and seems to be a promising route for both waste reduction, and the synthesis of value-added products such as oil sorbents. In this review, the research related to the production of various oil sorbents based on plastics (plastic waste and virgin polymer) has been discussed. Further oil sorbent efficiency in terms of oil sorption capacity has been described.

Oil spill remedy using bi-axially oriented polymer films

Oil spill on water surface and shorelines has been a major source of water pollution. With the damaging impact to ecology and the long term effects of environmental pollution, demand for materials for cleaning up the water in a quick and effective way has increased. A number of sorbents have been recommended for the purpose of picking up oil from water. These range from natural products, such as inorganic porous products and organic biodegradable products. However, most of them reveal limited oil sorption capacity and also absorb water. Hence, it is felt that there is a need of producing a synthetic oil sorbent that not only has high sorption capacity but also, unlike other contemporary synthetic sorbents, proves to be strong and cost effective. In this paper, we are presenting a novel super oil sorbent polymer (oil-sap) sheet consisting of ultrahigh molecular weight polyethylene (UHMWPE). The sorbent exhibits an uptake capacity of (276 g/g) and pickup density of (58 g/cm). In addition, it comprises a mechanically strong structure (tensile modulus and breaking stress of 1332 MPa and 171 MPa respectively). The unique blend of uptake capacity and strength along with cost effectiveness of the raw material (polyethylene) makes these sheets feasible candidates for mass production and application.

Effect of Acid Treatment on the Recovery of Valuable Metals from Steel Plant Exhaust

The response of different metals such as Zn, Fe, Pb, Cr and Mn during leaching of Electric Arc Furnace (EAF) dust in acid medium has been investigated. The major proportion of EAF dust constitutes of these metals and their recovery by means of a chemical process is not only economical but also imparts positive impact on the environment. The leaching of metals from dust is achieved using different concentration of sulphuric acid, and the dust samples have been characterized both before and after leaching. Based on the results, several recommendations have been suggested for the optimization of H 2 SO 4 concentration,that lead to the maximum recovery of these metals. Under the optimized conditions, it has been determined that the satisfactory leaching yield of Zn (95%) can be obtained at a concentration of 1M.