Touma B Issa

Redox flow batteries (RFBs) are known for their exceptional attributes, including remarkable energy efficiency of up to 80%, an extended lifespan, safe operation, low environmental contamination concerns, sustainable recyclability, and easy scalability. One of their standout characteristics is the separation of electrolytes into two distinct tanks, isolating them from the electrochemical stack. This unique design allows for the separate design of energy capacity and power, offering a significantly higher level of adaptability and modularity compared to traditional technologies like lithium batteries. RFBs are also an improved technology for storing renewable energy in small or remote communities, benefiting from larger storage capacity, lower maintenance requirements, longer life, and more flexibility in scaling the battery system. However, flow batteries also have disadvantages compared to other energy storage technologies, including a lower energy density and the potential use of expensive or scarce materials. Despite these limitations, the potential benefits of flow batteries in terms of scalability, long cycle life, and cost effectiveness make them a key strategic technology for progressing to net zero. Specifically, in Australia, RFBs are good candidates for storing the increasingly large amount of energy generated from green sources such as photovoltaic panels and wind turbines. Additionally, the geographical distribution of the population around Australia makes large central energy storage economically and logistically difficult, but RFBs can offer a more locally tailored approach to overcome this. This review examines the status of RFBs and the viability of this technology for use in Australia.

Exfoliated La-doped g-C3N4, namely La(x%)-eCN-N (x = 0.1%– 10%), was prepared via in-situ La doping and thermal treatment. The photocatalytic activity of La(x%)-eCN-N was explored through the degradation of methyl orange (MO) under visible light and then optimized by varying the loading of La dopant. The optimised La(1%)-eCN-N displayed an enhanced photocatalytic performance over the bulk and exfoliated g-C3N4, and bulk La-doped g-C3N4. Meanwhile, the use of La(1%)-eCN-N was seen with a high photocatalytic efficiency towards MO removal when compared with La(1%)-eCN-C, La(1%)-eCN-T, and La(1%)-eCN-U, which were prepared via conventional chemical, thermal and ultrasonic exfoliation of the pre-formed bulk La-doped g-C3N4. The observed outstanding photocatalytic activity of La(1%)-eCN-N was explained by several favourable features. In particular, the thin nanosheets would permit swift migration and effective separation of photogenerated charge carriers. The nitrogen adsorption–desorption analysis revealed an increased surface area and porosity, which might expose more active sites on the photocatalyst surface to adsorption and subsequent photocatalytic removal of MO molecules. Moreover, La(1%)-eCN-N was proven with improved visible light absorption, enhanced charge carrier separation and reduced transfer resistance. Its activity, along with the crystal and chemical characteristics, was largely retained after five cycles of photocatalytic reaction, affirming its good reusability and stability for potential practical application. The key reactive oxidising species involved in the photocatalytic removal of MO using La(1%)-eCN-N was experimentally determined to be the superoxide radical.

This study systematically studied the effects of Pr, Fe, and Na as representative rare earth, transition, and alkali metal dopants, respectively, on the photocatalytic activity of exfoliated graphitic carbon nitride (g-C 3 N 4). The doped exfoliated g-C 3 N 4 samples were prepared by integrating precursor ion intercalation into the pre-formed g-C 3 N 4 with thermal treatment. The as-prepared catalysts were examined for crystal, textural, chemical, optical, and photoelectrochemical properties to explore the correlation between dopants and photocatalytic activity of the resulting composites. The detailed analyses revealed that the Pr-doped g-C 3 N 4 exhibited superior photocatalytic activity in degrading methylene blue under visible light, achieving a ~96% removal in 40 min. This was not only better than the activity of g-C 3 N 4 , but also much higher than that of Na-doped g-C 3 N 4 or Fe-doped g-C 3 N 4. The kinetic rate constant using Pr-doped g-C 3 N 4 was 3.2, 5.1, and 2.0 times greater than that of the g-C 3 N 4 , Fe-doped g-C 3 N 4 , and Na-doped g-C 3 N 4 , respectively. The enhanced performance was attributed to its inherent characteristics after optimal tuning, including good surface area, improved porosity, enhanced visible light absorption, suitable electronic band structure, increased charge carrier density, promoted charge separation, and reduced charge transfer resistance. In addition, the optimized Pr(0.4)g-C 3 N 4 was used to study the photocatalytic removal of methylene blue in detail under conditions with different initial methylene blue concentrations, types of dyes, catalyst dosages, initial solution pH, counter ions, and water matrices. Our results demonstrated the high photocatalytic activity of Pr(0.4)g-C 3 N 4 under varying conditions, including in real wastewater media, which were collected from our local municipal wastewater treatment plant. The observed good reusability and stability after five cycles of photocatalytic degradation test further suggested a promising potential of Pr(0.4)g-C 3 N 4 for practical application in wastewater treatment.

For the first time, groundwater treatment sludge was integrated with g-C3N4 towards highly efficient and cost-effective visible-light-initiated catalysts for organic removal. The optimized sample of g-C3N4/GWS-M(2.5 %), which was synthesized using the sludge rich in Al and Fe, was explored with improved photocatalytic activity. Its photocatalytic performance was ∼6, 4, and 7 times that of g-C3N4 in terms of removal of methyl orange, cephalexin, and ketoprofen, respectively. The observed greater photocatalytic activity was attributed to its upgraded physicochemical properties, including specific surface area, porous structure, visible light absorption, charge separation and transfer. In particular, the co-existence of dominant Al and Fe dopants in g-C3N4/GWS-M(2.5 %) aided abstraction of photogenerated charge carriers. After photocatalytic reaction, only 0.02 % and 0.01 % loss of Al and Fe was observed from the catalyst, respectively. A superior organic removal (∼92 %) was still observed by using g-C3N4/GWS-M(2.5 %) with no change in its crystal and chemical structures at the 5th cycle of photocatalytic degradation. The primary reactive species responsible for the reaction were inferred to be the superoxide and singlet oxygen radicals.

Graphitic carbon nitride (g-C 3 N 4) is a promising material for photocatalytic applications. However, it suffers from poor visible-light absorption and a high recombination rate of photogener-ated electron–hole pairs. Here, Co/La@g-C 3 N 4 with enhanced photocatalytic activity was prepared by co-doping Co and La into g-C 3 N 4 via a facile one-pot synthesis. Co/La@g-C 3 N 4 displayed better performance, achieving 94% tetracycline (TC) removal within 40 min, as compared with g-C 3 N 4 (BCN, 65%). It also demonstrated promising performance in degrading other pollutants, which was ~2–4-fold greater relative to BCN. The improved photocatalytic activity of Co/La@g-C 3 N 4 was associated with improved photogenerated charge separation, reduced charge transfer resistance, a built-in electric field arising from the p-n-p heterojunction, and the synergistic effect of ternary components for the separation and transfer of the photogenerated charge carriers. Superoxide radicals are suggested to be the most notable reactive species responsible for the photocatalytic reaction. Environmental factors, including the pollutant concentration, catalyst dosage, solution pH, inorganic salts, water matrices, and mixture with dyes, were considered in the photocatalytic reactions. Co/La@g-C 3 N 4 showed good reusability for five cycles of the photocatalytic degradation of TC. The facile one-pot co-doping of Co and La in g-C 3 N 4 formed a p-n-p heterojunction with boosted photocatalytic activity for the highly efficient removal of TC from various water matrices.

This paper aims to examine the challenges of and perceptions about promoting students’ learning, communication, and interaction via the Wiki tool in the blackboard platform. Wiki intends to sustain and advance students’ professional and personal skills, the former ones including reading, writing, research, information, critical thinking, decision making, technology, digital oral presentation, drawing (i.e. concept maps), teamwork, and languages, and the latter ones including motivation, leadership, negotiation, communication, problem solving, time management, reflection, self-management, and self-appraisal. Additionally, integrating Wiki in teaching and learning will improve students’ work performance, productivity, and self-confidence, as these skills are needed for not only the current study, but also the workplace in the future. Additionally, using this tool in teaching and learning, especially in the higher education, can bring some challenges to the lecturer and students, particularly in the presentation and marking. This paper will discuss the Wiki implementation in the postgraduate unit at an Australian university. The study results confirmed that using Wiki in the postgraduate unit at an Australian university enhanced students’ personal and professional skills; in addition, students learned and absorbed the new concepts and cutting-edge-knowledge of the ITS65 unit, i.e. sustainability and Green IT.

The adsorption performance of bauxite for the removal of As(V) and As(III) from contaminated water was investigated. The effect of initial pH, contact time, and the presence of silicate, phosphate and chloride, at concentrations typically found in the ground drinking water in India/Bangladesh, were investigated. As(V) is adsorbed at a rapid initial rate (>96% adsorption within 1 minute) followed by a slow process, reaching a steady state within 6 hours. In comparison the adsorption of As(III) is slow, only 40% is adsorbed within the first minute that gradually rises to 85% in 6 hours. The presence of chloride has insignificant effect on both As(III) and As(V) adsorption. Silicate and phosphate both significantly affect adsorption of both the arsenic ions. Phosphate affects adsorption more strongly than silicate and their effect on As(III) is higher than As(V). When silicate and phosphate are present together, the adsorption of As(V) is almost the same as for the individual ions. However, the As(III) adsorption is significantly affected. The adsorption is 61% as compared to 73% for silicate and 71% for phosphate when individually present. While chloride alone has insignificant effect on the adsorption of the arsenic ions, it has some influence when present together with silicate or phosphate. Chloride + Phosphate combination increases As(V) adsorption by 3% and As(III) by 8%. Chloride + Silicate combination increases As(V) adsorption by 9% but decreases As(III) by almost the same percentage. As compared to the influence of silicate + phosphate, the combination of the three ions together, lowers the As(V) adsorption by 4% and increases As(III) by 4%.

Measurement of state-of-charge of lead-acid batteries using potentiometric sensors would be convenient; however, most of the electrochemical couples are either soluble or are unstable in the battery electrolyte. This paper describes the results of an investigation of poly (divinylferrocene) (PDVF) and Poly(diethynylanthraquinone) (PAQ) couples in sulfuric acid with the view to developing a potentiometric sensor for lead-acid batteries. These compounds were both found to be quite stable and undergo reversible reduction/oxidation in sulfuric acid media. Their redox potential difference varied linearly with sulfuric acid concentration in the range of 1 M - 5 M (i.e. simulated lead-acid electrolyte during battery charge/discharge cycles). A sensor based on these compounds has been investigated.

Goethite nanoparticles synthesized using hydrazine sulfate as a modifying agent were evaluated for As(V) adsorption capacity. The nanoparticles were characterized for their morphological and structural features. The precipitated goethite particles were spherical with particle size of less than 10 nm. Batch adsorption study was carried out systematically varying parameters such as pH, contact time, initial As(V) Concentration and adsorbent doses. The Langmuir isotherm represented the equilibrium data well and the estimated monolayer adsorption capacity at ambient temperature was 76 mg/g, which is significantly higher than most of the adsorbents reported in the literature. Adsorption kinetic data were better represented by the pseudo-second order kinetic model. Intra-particle diffusion played a significant role in the rate controlling process in the initial hour. Desorption study showed that the loaded adsorbent could be regenerated when treated with dilute sodium hydroxide solution of pH 13.

Determination of inorganic phosphate is of very high importance in environmental and health care applications. Hence knowledge of suitable analytical techniques available for phosphate sensing for different applications becomes essential. Electrochemical methods for determining inorganic phosphate have several advantages over other common techniques, including detection selectivity, stability and relative environmental insensitivity of electroactive labels. The different electrochemical sensing strategies adopted for the determination of phosphate using selective ionophores are discussed in this review. The various sensing strategies are classified based on the electrochemical detection techniques used viz., potentiometry, voltammetry, amperometry, unconventional electrochemical methods etc., The enzymatic sensing of phosphate coupled with electrochemical detection is also included. Various electroanalytical methods available in the literature are assessed for their merits in terms of selectivity, simplicity, miniaturisation, adaptability and suitability for field measurements.