Graphene and chemically modified graphene can be fabricated via numerous routes each with its own merits concerning ease of processability, cost-effectiveness for large-scale production, and also health and safety. One of the promising applications of graphene-based composites is gas sensing, which is mainly useful for environmental monitoring. We review some of the significant findings on graphene-based sensing materials for the detection of organic vapors, toxic gases, and chemical warfare agent simulants using an electrochemical method. Electrochemical sensing can be performed by inducing interactions between gas molecules and a graphene layer, such as charge transfer that gives a change in an electrical signal. The intrinsic properties of graphene and its role in some gas sensing applications will be discussed. Graphene and graphene oxide (GO) work as continuous conductive networks with a large number of surface adsorption sites for many gas molecules. Hybrid graphene devices incorporate semiconductors, metals, and molecular binders to enhance the capabilities of solidstate gas sensors. This article also addresses current approaches to the commercialization of graphene-based gas sensors.

Immobilization is a method for making an enzyme more robust in the environment, especially in terms of its stability and reusability. A mutant phosphotriesterase (YT PTE) isolated from Pseudomonas dimunita has been reported to have high proficiency in hydrolyzing the Sp and Rp-enantiomers of organophosphate chromophoric analogs and therefore has great potential as a decontamination agent and biosensor. This work aims to investigate the feasibility of using Fuller’s earth (FE) as a YT PTE immobilization support and characterize its biochemical features after immobilization. The immobilized YT PTE was found to show improvement in thermal stability with a half-life of 24 h compared to that of the free enzyme, which was only 8 h. The stability of the immobilized YT PTE allowed storage for up to 4 months and reuse for up to 6 times. The immobilized YT PTE showed high tolerance against all tested metal ions, Tween 40 and 80 surfactants and inorganic solvents. These findings showed that the immobilized YT PTE became more robust for use especially with regards to its stability and reusability. These features would enhance the future applicability of this enzyme as a decontamination agent and its use in other suitable industrial applications.

Cellulose nitrate has attracted great interest amongst researchers due to its uses in wide range of products including paint and gun propellant. Therefore, this work focuses on the synthesis of cellulose nitrate from two different sources of cellulose; plant and bacterial, in order to obtain high percentage of nitrogen content hence suitable for propellant application. The synthesis of cellulose nitrate was carried out via nitration method using nata de coco and kapok (Ceiba pentadra L) as a raw materials of cellulose. The samples were then characterized by elemental analysis, fourier transform infrared (FTIR) spectroscopy, x-ray diffraction and surface electron morphology (SEM). FTIR analysis showed the presence of NO2 groups in both nitrocellulose proving that nitrocellulose was successfully synthesized by nitration method even though it was produced from different sources of cellulose. It is also showed nitrocellulose with high percentage of nitrogen content was obtained from bacterial cellulose, 12.69% rather than plant cellulose.

We successfully optimized AuNPs, modified DNA aptamer and magnesium sulphate salt to enhance the selectivity and sensitivity for detection of Ac. The accuracy of the detection was also improved by image processing technique.

Exposure and misuse of organophosphate (OP) compounds originated from insecticides, drugs and chemical warfare agents are potential hazard to health and environment. OP detection is one of the four strategies (deter, detect, delay, and defend) to protect vulnerable from this chemical threat. Among many methods to detect OP, electrical-based detection and graphene nanomaterials deliver higher sensitivity performance, technological compatibility, and versatility. The magic of graphene originates from its large surface area and excellent electrical conductivity, while electrical methods offer low cost, rapid, and easy handling. This article provides an overview of selected electrical and electrochemical methods employing graphene, reduced graphene oxide, graphene oxide, and other graphene forms reported for OP detection in the recent years. Strategies in using graphene, experimental challenges and fundamental material interactions including advantages using biomaterials as receptors in achieving better detection limit, specificity, and selectivity of OP compounds are the highlights of the paper. Every transformation of graphene has its merits in term of ease of processing, device functionality and sustainability. Since contemporary graphene had successfully reached low detection limit possible in OP sensing, graphene sensor device should be focused on developing rapid and in-situ OP monitoring in water and food resources to alert authorities on possible contamination in the community.