Clean Alternatives Research Articles

Continuous production of hydroxyapatite Pickering emulsions using a mesostructured reactor

Emulsions are used in a wide range of applications, including food and cosmetics. Nowadays, the demand for sustainable products has increased with Pickering emulsions emerging as clean alternatives. To achieve the industrial implementation of Pickering emulsions, continuous production and less intensive energy devices are required. In this context, a mesostructured reactor based on an innovative static mixer, NETmix, was tested to produce Pickering emulsions from a previously developed formulation in batch mode. The effect of the number of cycles (2–35) and Reynolds number (200–500), parameters that influence the residence time and the quality of mixing, on the Pickering emulsion properties (average droplet size, droplet morphology, and stability) was studied. The obtained results pointed out the feasibility of using NETmix to produce Pickering emulsions. It is a versatile technique to control in a tailor-made way the droplet size and generate small droplets at short times. Results show a decrease of the droplet size with increasing number of cycles and Reynolds. Under the tested conditions, stable dispersions with droplet size of ∼7 μm were produced using 17 cycles and Re = 400. Microscopy images show an oil core and nano-hydroxyapatite shell morphology.

Siting strategy for co-locating windfarms and radars considering interference constraints

As the energy sector moves away from use of fossil fuels towards clean renewable energy alternatives, the technical impediment of windfarm interference with radars has dented the deployment of windfarms. This paper provides a step-by-step siting methodology for co-locating windfarms and radars with the support of simulation tools. A procedural framework for co-locating windfarms and radars is suggested. The proposed methodology identifies crucial variables, such as azimuth, frequency, and topographical features affecting the co-existence of radars and windmills. The effect of variables on radar cross-section for feasible radar frequency ranges between 0.1 GHz and 10 GHz is calculated. The siting methodology suggests use of digital terrain maps for evaluating the interference impact due to terrain screening. In case of inextricable circumstances, where radar needs to be sited in high impact zones near windfarms, suitable mitigation techniques are suggested.

Catalytic hydrocracking of synthetic polymers into grid-compatible gas streams

The use of methane as one of the cleanest energy sources has attracted significant public awareness, and methane production processes with less environmental impact than fracking are receiving considerable attention. Catalytic hydrocracking of plastic materials has been considered a potential clean alternative. However, catalysts that convert heterogeneous plastic feeds into a single product under industrially relevant conditions are lacking. Here, we describe a Ru-modified zeolite that catalytically transforms polyethylene, polypropylene, and polystyrene into grid-compatible methane (>97% purity), at 300°C–350°C using near-stoichiometric amounts of H2. Mechanistic studies reveal a chain-end initiation process with limited isomerization of plastic substrates. A Ru site-dominant mechanism is proposed based on these studies and density functional theory (DFT) computations. We foresee that such a plastic-to-methane process may increase the intelligent use of plastic waste via energy recovery. There is also the potential to accommodate emerging sustainable H2 production into existing natural gas networks, while integrating waste management, fuel production, and energy storage.

Cages’ farming foundation as a limiting factor in cultivation of sturgeon fish hybrids

The work experimentally confirmed the negative influence of fouling of cage structures on the growth and survival rates of reared young sturgeon hybrid — bester (Huso (Linnaeus, 1758) × Acipenser ruthenus (Linnaeus, 1758)). A significant decrease in growth and an increase in fish mortality in modules with a maximum biofouling area was noted. The possibility of using alternative cleaning methods in comparison with traditional mechanical and chemical ones has been investigated. The positive results of the experimental approbation of the author’s development — the practical application of a specially designed structure made of tarpaulin for the cage are given. The use of an easy-to-manufacture and operate device prevented active contamination of the cells, increased the efficiency of keeping fish, which is economically beneficial for commercial sturgeon growing in cages. In general, in fish farms located in a natural reservoir in the spring-summer period, the overgrowth of fodder bottoms and cage walls with filamentous algae has a strong negative effect on the cultivation of sturgeon fish. To optimize the fish-breeding process and reduce the number of algae during the period of their active growth on cages (the timing must be determined according to the conditions of a particular reservoir), special canvas covers should be used. This device will reduce the amount of sunlight entering the cage bottoms and slow down the growth of filamentous algae. To install this device on the cage, two workers are required, the approximate installation time (and, if necessary, dismantling) will be 20 minutes. To reduce the negative effect of algae fouling of the cage bed, measures should be taken to mechanically clean the stern bottoms and walls of the cage with high-pressure cleaning (washer) devices, after transplanting the cultivated objects into another fish hatchery

Development of Activated Carbon from Pineapple Crown Wastes and Its Potential Use for Removal of Methylene Blue

ABSTRACT The use of agro-industrial residues to produce biomass-based activated carbon to remove methylene blue may be one of the most promising alternatives to solve industrial wastewater problems, as well as agro-industrial waste. This work purposes an alternative for the development of pineapple crown waste (PC) as activated carbon (ACPC) by chemical activation using NaOH and pyrolysis for the removal of methylene blue (MB). The material was characterized by CHNS-O, SEM, BET, XRD, FTIR, and TGA. For the non-linear study of the Langmuir, Freundlich, and Temkin isotherms, the parameter investigated was the initial concentration (10, 25, 50, 100, 250, and 500 mg.L−1). Experimental results revealed the suitability of pineapple crown waste to be used as a precursor for activated carbon. According to the Langmuir non-linear model, ACPC presented a maximum adsorption capacity of 292 mg.g−1. The good MB removal capacity by ACBP is due to pores structure. Pineapple crown waste can be used as an alternative cleaner for an ecologically adsorbent.

Direct hematite flotation from an iron ore tailing using an innovative biosurfactant

ABSTRACT The use of a biosurfactant (BS) in mineral flotation offers numerous advantages over conventional surfactants, such as their low toxicity, high degradation kinetics, and potential for selectively treating low-grade ores. In the present study, the use of a biosurfactant obtained from Rhodococcus opacus bacteria for the flotation of hematite from iron ore tailings was evaluated. The microflotation assessments were conducted in a modified Partridge-Smith cell, and the batch flotation studies were conducted in a mechanical cell (CDC – cell). In addition, the effects of the pH, biosurfactant concentration, and depressant concentration on hematite recovery were evaluated. The results confirmed the biosurfactant adsorption onto the hematite surface, and the biosurfactant decreased the surface tension of the water/gas interface. The critical micelle concentration (CMC) of the biosurfactant was approximately 1 g.L−1. Hematite recovery was feasible at a pH of around 3. In microflotation tests, the iron grade and recovery reached approximately 37% and 30%, respectively. These values increased in batch flotation circuits, specifically in the cleaner stage, the iron grade reached approximately 44% and the recovery was approximately 65%. Thus, the current development proved that this particular treatment of ore tailings carries environmental and technical benefits as an appropriate alternative cleaning technology.

Modeling analysis of typical equipment and construction of energy supply scenarios for electric energy substitution

This paper studies the design of clean electric energy alternatives based on electric energy alternative equipment. First, sort out the current research status of energy substitution at home and abroad, and determine the research focus of electric energy substitution; list the electric energy substitution equipment that is suitable for construction, industrial, commercial and other fields, analyze its technical characteristics and specific application scenarios; list each device To analyze the performance of the equipment, establish a multi-factor output model for energy storage and production equipment according to the key influencing factors of the equipment performance coefficient; finally, based the above research, consider the substitutability of each equipment With complementary characteristics, the design is suitable for high-clean energy electric energy to replace typical structures.

Air pollution and neurological development in children.

Pregnancy and early childhood are periods with high plasticity in neurological development. Environmental perturbations during these sensitive windows can have lifelong developmental consequences. This review summarizes key findings relevant to the effects of air pollution on neurological development. Mounting evidence suggests that exposure to air pollution, both during pregnancy and childhood, is associated with childhood developmental outcomes ranging from changes in brain structures to subclinical deficits in developmental test scores, and, ultimately, developmental disorders such as attention-deficit/hyperactivity disorders or autism spectrum disorders. Although the biological mechanisms of effects remain to be elucidated, multiple pathways are probably involved and include oxidative stress, inflammation, and/or endocrine disruption. Given the alarming global increase in developmental disorders in recent years, and increased human exposures to pollution, it is critical to reduce personal and community-level exposures through tight collaboration of interdisciplinary and multi-level bodies including community partners, physicians, industry partners, policy makers, public health practitioners, and researchers. WHAT THIS PAPER ADDS: Exposure to air pollution is associated with a range of childhood developmental complications. Biological mechanisms may include oxidative stress, inflammation, and endocrine disruption.

\Effect of some Weed Control Practices on Coriander (Coriandrum sativum L.) Productivity and their Associated Weeds

Two field experiments were carried out during 2016/2017 and 2017/2018 winter seasons at Sids Horticultural Research Farm, Egypt, to evaluate the efficacy of eleven weed control treatments on weeds and coriander productivity with monitoring chemically herbicidal residues by HPLCinbothsoil and coriander seeds in randomized complete block design with four replicates. The results show that coriander seed yield losses due to weed competition varied from 56.6-55.5 percent through the course of this study. Hand hoeing thrice, black polyethylene mulch, rice straw mulch and Stomp extra at 1.7 l/feddan treatments gave 8.95-6.90 percent of weed control accompanied with coriander increases seed yield varied from 200.9-230.5 percent than unweeded check. Such increases in seed yield per feddan are positively correlated with various studied yield components and negatively with various studied weed categories emphasizing the need of good weed control program in coriander crop production with less herbicide residues, which determined by HPLC in both soil and seed coriander were below than the maximum residue allowable level expect with Ultra afalon at 1.0 l/fed. in the soil. Economic evaluation, showed that seed yield of coriander is a profitable enterprise for coriander growers by using hand hoeing thrice or Stomp extra or black polyethylene mulch and rice straw mulch treatments which can be recommended as good and clean alternatives for weed control in coriander crop.

Offshore wind energy – South Africa’s untapped resource

In the context of the Anthropocene, the decoupling of carbon emissions from electricity generation is critical. South Africa has an ageing coal power fleet, which will gradually be decommissioned over the next 30 years. This creates substantial opportunity for a just transition towards a future energy mix with a high renewable energy penetration. Offshore wind technology is a clean electricity generation alternative that presents great power security and decarbonisation opportunity for South Africa. This study estimated the offshore wind energy resource available within South Africa’s exclusive economic zone (EEZ), using a geographic information system methodology. The available resource was estimated under four developmental scenarios. This study revealed that South Africa has an annual offshore wind energy production potential of 44.52 TWh at ocean depths of less than 50 m (Scenario 1) and 2 387.08 TWh at depths less than 1 000 m (Scenario 2). Furthermore, a GIS-based multi-criteria evaluation was conducted to determine the most suitable locations for offshore wind farm development within the South African EEZ. The following suitable offshore wind development regions were identified: Richards Bay, KwaDukuza, Durban, and Struis Bay. Based on South Africa’s annual electricity consumption of 297.8 TWh in 2018, OWE could theoretically supply approximately 15% and 800% of South Africa’s annual electricity demand with offshore wind development Scenario 1 and 2 respectively.

A perspective on the use of ammonia as a clean fuel: Challenges and solutions

A perspective on the use of ammonia as a clean fuel: Challenges and solutions

Enhancement of Releasing Phosphorus from Bone Char in Calcareous Sandy Soil Under Applying Different Levels of Water Salinity

The high cost of phosphate fertilizers, as well as pollution with heavy and radioactive elements, motivated us to find clean alternatives for phosphate fertilizers to conserve the environment such as bone char. Also, the groundwater used in the agricultural activity of desert soils is considered to be saline. Therefore, the specific objective of this incubation experiment was to investigate the application of bone char with different levels of water salinity on changes of phosphorus (P) availability and some soil quality indicators of calcareous sandy soil. The results of this study revealed that applying bone char (BC) combined with saline water significantly increased the available P (Olsen-P) in calcareous sandy soil compared to the control (unamended soil) and bone char with distilled water treatment. The P release from bone char increased with increasing water salinity levels. The increase of incubation time results in an increment of Olsen-P concentration at a high level of saline water. Soil pH values declined with the addition of bone char combined with saline water, while the electrical conductivity (EC) of the soil in this study increased gradually with increasing the water salinity level in the presence of bone char. The soluble sulfate (SO42−) increased by applying bone char and saline water. Based on this, we can suggest the use of bone char under the presence of saline water as an alternative to phosphate fertilizer, especially in sustainable agriculture because it is economically and environmentally friendly. The bone char can be a substitute for chemical fertilizers produced from rock phosphate.

Differences in firewood users’ and LPG users’ perceived relationships between cooking fuels and women’s multidimensional well-being in rural India

Clean cooking fuels are generally assumed to bring health and other benefits for women compared with solid fuels, which suggests they should be preferred. However, despite the availability of clean cooking fuels, such as liquefied petroleum gas (LPG), the scale of solid fuel use in rural India remains large. Here we examine women’s positions on fuel transition and multidimensional well-being through a qualitative analysis of data from focus group discussions with comparable groups of women who have versus those who have not transitioned to LPG. We show that women who use firewood believe their cooking fuel supports their well-being in several ways, and see no enabling relationship between LPG use and well-being. In contrast, LPG users—who were previous firewood users—claim LPG has enabled well-being. These results suggest that perspectives on the relationship between fuel and well-being shift after transition, due to the realization of new advantages. Understanding differences in the perspectives of women using different fuels is vital to unpack the dynamics of cooking fuel transition. There is consensus that using firewood negatively impacts women’s well-being, suggesting that clean alternatives will be preferred. However, this study finds that women have different views on how cooking with firewood and LPG support well-being depending on the fuel they currently use.

Drivers and critical supply chain paths of black carbon emission: A structural path decomposition

As the second largest factor contributing to global warming, black carbon (BC) is also the main cause of smog pollution in Chinese cities and has negative influence on residential health. In this paper, structural decomposition analysis (SDA) and structural path decomposition (SPD) are jointly used to identify the socioeconomic factors and critical supply chain paths driving consumption-based BC changes in Sichuan Province, which has become a main BC emission source since the implementation of “Western Development Strategy”. The SDA results show that economic growth contributes 75.02 kt emission increase. Emission intensity plays a critical role in emission reduction, which offsets the emission increase by 56.00 kt. The results of SPD identify that the major paths influencing BC emission changes are “Petroleum Processing→(Construction/Metal Smelting and Production/Machinery and Equipment)→Final Demand,” “Agriculture→(Food Production/Agriculture)→Final Demand,” and “Transportation→(Commercial and Institution)→Final Demand.” Socioeconomic drivers might pose a bidirectional impact on BC emission on different supply paths. The results reveal that BC reduction should emphasize reducing the emission intensity of the upstream sector, improving the production efficiency of the intermediate sector, and using cleaner alternatives in the downstream sectors on critical paths. The case of Sichuan may provide insights into the BC mitigation practices of other regions.

Sustainability of hydrogen refuelling stations for trains using electrolysers

Hydrogen has the potential to become a powerful energy vector with different applications in many sectors (industrial, residential, transportation and other applications) as it offers a clean, sustainable, and flexible alternative. Hydrogen trains use compressed hydrogen as fuel to generate electricity using a hybrid system (combining fuel cell and batteries) to power traction motors and auxiliaries. This hydrogen trains are fuelled with hydrogen at the central train depot, like diesel locomotives. The main goal of this paper is to perform a techno-economic analysis for a hydrogen refuelling stations using on-site production, based on PEM electrolyser technology in order to supply hydrogen to a 20 hydrogen-powered trains captive fleet. A sensitivity analysis on the main parameters will be performed as well, in order to acquire the knowledge required to take any decisions on implementation regarding electricity cost, hydrogen selling price, number of operation hours and number of trains for the captive fleet.The main methodology considers the evaluation of the project based on the Net Present Value calculation and the sensitivity analysis through standard method using Oracle Crystal Ball. The main result shows that the use of hydrogen as an alternative fuel for trains is a sustainable and profitable solution from the economic, environmental and safety points of view.The economic analysis concludes with the need to negotiate an electricity cost lower than 50 €/MWh, in order to be able to establish the hydrogen selling price at a rate higher than 4.5€/kg. The number of operating hours should be higher than 4800 h per year, and the electrolyser system capacity (or hydrogen refuelling station capacity) should be greater than 3.5 MW in order to reach a Net Present Value of 7,115,391 € with a Return of Investment set to 9 years. The result of the multiparametric sensitivity analysis for the Net Present Value (NPV) shows an 85.6% certainty that the project will have a positive result (i.e. profitability) (NPV> 0). The two main variables with the largest impact on Net Present Value are the electrolyser capacity (or hydrogen refuelling station capacity) and the hydrogen selling price. Moreover, a margin of improvement (higher NPV) could be reached with the monetization of the heat, oxygen by-product and CO2 emission reduction.

Moving from Fossil Fuels to Electric Cooking: An Option for Clean Cooking Access in Nepal

Nepal has abundant hydropower potential and generation capacity under construction that should be able to meet the growing energy need of the country. Although access to electricity in the country is increasing, adoption and access to clean cooking facilities remains insignificant, as about 85% of the population still rely on solid fuels to meet their daily cooking needs. In this regard, energy generated from hydropower can play the dual role of providing access to modern energy as well as providing a clean cooking alternative that is clean and sustainable. Having realized this, the Ministry of Energy, Water Resources and Irrigation has issued a white paper (point 73) for the ‘Electric Stove in Every House’ Programme, which is expected to encourage the use of electric cooking. This gives an opportunity not only to make use of Nepal’s hydropower resources but also to reduce its dependence on imported fossil fuel. Our paper discusses the challenges and opportunities for introducing electricity in the cooking fuel mix in Nepal from the policy perspective. We draw upon the review of lessons learned from other countries including Ecuador, Bhutan and South Africa, to illustrate the potential pathways for the transition of fossil fuel-based products to electricity in Nepal. These countries have used a combination of approaches in including electricity in their cooking fuel mix, such as favourable electricity pricing, import tariff reductions in cooking appliances, and developing national policy and programmes to facilitate the integration of electricity in cooking fuel. These lessons from these countries are used to recommend pathways for moving from fossil fuel-based products to electricity in Nepal’s context.

Current Development in Decolorization of Synthetic Dyes by Immobilized Laccases.

The world today is in a quest for new means of environmental remediation as the methods currently used are not sufficient to halt the damage. Mostly, a global direction is headed toward a shift from traditional chemical-based methods to a more ecofriendly alternative. In this context, biocatalysis is seen as a cost-effective, energy saving, and clean alternative. It is meant to catalyze degradation of recalcitrant chemicals in an easy, rapid, green, and sustainable manner. One already established application of biocatalysis is the removal of dyes from natural water bodies using enzymes, notably oxidoreductases like laccases, due to their wide range of substrate specificity. In order to boost their catalytic activity, various methods of enhancements have been pursued including immobilization of the enzyme on different support materials. Aside from increased catalysis, immobilized laccases have the advantages of higher stability, better durability against harsh environment conditions, longer half-lives, resistance against protease enzymes, and the ability to be recovered for reuse. This review briefly outlines the current methods used for detoxification and decolorization of dye effluents stressing on the importance of laccases as a revolutionary biocatalytic solution to this environmental problem. This work highlights the significance of laccase immobilization and also points out some of the challenges and opportunities of this technology.

Cyanobacterial Polyhydroxyalkanoates: A Sustainable Alternative in Circular Economy.

Conventional petrochemical plastics have become a serious environmental problem. Its unbridled use, especially in non-durable goods, has generated an accumulation of waste that is difficult to measure, threatening aquatic and terrestrial ecosystems. The replacement of these plastics with cleaner alternatives, such as polyhydroxyalkanoates (PHA), can only be achieved by cost reductions in the production of microbial bioplastics, in order to compete with the very low costs of fossil fuel plastics. The biggest costs are carbon sources and nutrients, which can be appeased with the use of photosynthetic organisms, such as cyanobacteria, that have a minimum requirement for nutrients, and also using agro-industrial waste, such as the livestock industry, which in turn benefits from the by-products of PHA biotechnological production, for example pigments and nutrients. Circular economy can help solve the current problems in the search for a sustainable production of bioplastic: reducing production costs, reusing waste, mitigating CO2, promoting bioremediation and making better use of cyanobacteria metabolites in different industries.

Theoretical and Experimental Performance Analysis of a Novel Domestic Biogas Burner

The inefficient indoor burning of fuelwood on traditional cookstoves generates pollutants, primarily carbon monoxide and many other human health-damaging emissions. It is from this risk that it is necessary to have an immediate shift to alternative cleaner fuel sources. Biogas, which is among the biofuels from biomass, is one of the resources that play a considerable part in a more diverse and sustainable global energy mix. For domestic purposes in rural areas of Tanzania, biogas provides a better option that can supplement the use of fossil fuels such as wood, charcoal, and kerosene, which is nonrenewable. However, the low efficiency experienced in the locally made biogas burners hinders the large-scale use of biogas among the population in the country. With the locally made burners, the users of biogas for the domestic application face problems including heat loss and high gas consumption which affects the whole cooking process. It is against this backdrop that the current study objectives incline on designing and improving the efficiency of the locally manufactured burners to achieve the uniform flow of fuel in the mixing chamber, which will result to the consistent heat distribution around the cooking pot. The optimization of the burner was done by using computational fluid dynamics (CFD) through varying the number of flame portholes and air holes as well as the size of the jet before fabrication. The increased efficiency of the burner has also contributed by the addition of the fuel distributor. The results showed that the optimum hole diameter of the jet was 2.5 mm and that of the manifold was 100 mm. The currently developed biogas burner was tested and compared with the other two locally made burners. The water boiling test (WBT) on these three burners showed that the developed burner has a thermal efficiency of 67.01% against 54.61% and 58.82% of the Centre for Agricultural Mechanization and Rural Technology (CARMATEC) and Simgas, respectively. Additionally, the fuel consumption of the developed burner was 736 g/L as compared to 920 g/L for CARMARTEC and 833 g/L for that of Simgas. The developed burner and its corresponding cookstove are both environmentally friendly and economical for household utilization in Tanzania and other developing countries.

Comparison of Planar and Tubular Flow Field Plates for Proton Exchange Membrane Fuel Cells (PEMFCs) through Simulation

Proton exchange membrane fuel cells are excellent clean energy alternatives to current non-renewable energy sources. Bipolar plates are a key component of these fuel cells and directly responsible for their performance. Traditional bipolar plates are created in a planar form, but recent research has revealed a novel tubular design that performs similarly to conventional plates. This study compares traditional planar designs with tubular ones. The finite element ANSYS software was used to determine and visualize velocity and pressure distributions of fluid flow through the bipolar plate channels.