Search

The availability of agricultural wastewater in arid climes limits the possibility of exploiting purple non‐sulfur bacteria (PNSB) to recover aqua‐feed bioproducts. Thus, this study examines the feasibility of recovering such bioproducts using fuel‐synthesis process water (FSPW) as a feedstock. Experiments were performed under varying light conditions. The results revealed that PNSB cultured in the zero‐nitrogen feedstock had over 40 % protein content, contained substantial lipids and pigments, and reduced FSPW organics by over 70 %. The light intensity significantly impacted biomass constituents and treatment efficiency. The results are promising for the potential development of a circular economy to convert FSPW to aqua‐feed. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adsorption has been widely applied in wastewater treatment for heavy metal removal. Due to the high cost of adsorbent materials, various types of materials including agricultural, industrial wastes and naturally abundant materials have emerged as low‐cost adsorbents in recent years. However, enhancement processes need to be developed to improve the adsorption capability of the raw materials. It is still a challenge to find an economic material with high adsorption capacity. This paper demonstrates a strategy to activate a recycled waste material using a simple activating process, while significantly improving the adsorption capacity of cadmium from wastewater. RESULTS: The raw material feedstock is the non‐metallic aluminosilicate material obtained from the recycling of waste printed circuit boards (PCBs). By a simple thermal alkali activation process using potassium hydroxide as activation agent, the product material shows a strong capability of cadmium removal from effluent containing a high adsorption capacity of 2.12 mmol g−1. Initial metal concentration, dosage and pH effect on the adsorption isotherm and kinetics have been investigated. The experimental results include full characterization tests on this waste PCB‐derived adsorbent, and the in situ measurement of cadmium, calcium and potassium ions, since all are involved in the exchange sorption mechanism. CONCLUSION: By combining kinetic modelling analysis and X‐ray photoelectron spectroscopy, the novel adsorption mechanism has been explained and quantified as a dual ion‐exchange mechanism with the millimoles of cadmium exchanged mass balancing with the millimoles of calcium and 0.5 mmol potassium going into solution. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The development of improved catalysts for the hydrogenation of CO2 into methane is a sustainable response to the energy crisis and environmental problems at the global level. Mn‐Ce/N‐TiO2 heterojunctions, comprising a Mn‐Ce concretion composite, were prepared using a sol–gel technique, and the photocatalytic hydrogenation of CO2 was studied using visible light as alternative driving energy. The photocatalyst composite was characterized, and synergistic effects on the photocatalytic hydrogenation of CO2 into methane were investigated. The characterization results confirmed that there was a considerable shifting of band‐gap energy towards the visible range with required properties, which enhances photocatalytic activities under natural sunlight. Carbon dioxide hydrogenation and its potential for conversion into methane was evaluated using a specially designed photoreactor and different light sources. The results show a CO2 hydrogenation rate of about 16.8% ±0.2 in a visible light‐assisted catalytic reduction process in 60 min. The irradiation time and light source were studied and significant impacts on CO2 hydrogenation were observed under a LED light source and with H2O vapor as a reducing agent (up to 23.4% ± 0.2). The effect of photocatalysis on the methane yield in the anaerobic digestion (biomethanation) process was evaluated and a potential methane yield of up to 13.5% within 24 h was observed. The results suggested promising and sustainable applications of the Mn‐Ce/N‐TiO2 heterojunction composite for CO2 hydrogenation and for the conversion of CO2 into fuel and methane in the biomethanation process. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

The widely used toxic dye malachite green (MG) poses a significant risk to human health, having a mutagenic effect. Waste date stones were used to produce microwave‐activated carbons and were applied to adsorb the highly toxic dye. The critically important task of selecting the correct design adsorption capacity for different effluent pollutant concentrations to meet effluent discharge limit standards is described and a novel design selection criteria approach is presented. [ABSTRACT FROM AUTHOR]

Selective sorption of oil using plastic waste is presented. Plastic solid waste constitutes 15% of total municipal solid waste produced across the world and is mostly either discarded in landfills or incinerated. On the other hand, pollution caused by oil spill in aquatic locations is a serious environmental concern, and several sorbents have so far been proposed to address oil spill and plastic waste problems simultaneously by converting waste into oil sorbent. However, most of the sorbents have drawbacks of either high water uptake or low oil uptake capacity. In this study, we have synthesized oil sorbent using waste plastic bottles made up of high-density polyethylene with high selectivity and high oil uptake capacity. Mechanical properties and %crystallinity using differential scanning calorimetry were also determined to provide useful insight about the as prepared sorbent. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The usage of natural and synthetic sorbents in order to control oil spills is gaining increasing attention due to environmental concerns. In particular, polyolefins including polypropylene and polyethylene are the most commonly used oil sorbent materials because of their low cost but suffer from low oil absorption capacity. Attempts at trying to increase the surface-to-thickness ratio for improving uptake capacity makes them vulnerable to breakage and impractical for most oil spill applications. Novel super oil sorbent polymer sheets consisting of porous ultrahigh-molecular-weight polyethylene have been prepared. The presented sorbent exhibits extremely high uptake and retention capacities along with a mechanically strong structure. The combination of these factors as well as the cost effectiveness of the material used makes these sheets viable candidates for widespread production and utilization. [ABSTRACT FROM AUTHOR]

This paper presents the oil uptake of porous sorbent polymer sheets consisting of ultra-high molecular weight polyethylene. A comprehensive set of experiments are performed showing the saturation contact time, retention value, mechanical properties, oil pick-up ratio, pick-up density, and dynamic dripping profile. Kinetic modeling of the oil sorption is also provided. The experimental results show a good correlation with the pseudo-second order model. The sheets exhibit high oil uptake speeds, requiring less than 2 min in contact with the oil to reach saturation. The sheets fulfill the criteria of high uptake kinetics, high sorption capacity, and high mechanical strength simultaneously. Those characteristics enable their use in practical spill response. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]