Soil Chemical Analysis

Sustainability is a key principle in natural resource management, and it involves operational efficiency, minimisation of environmental impact and socio-economic considerations; all of which are interdependent. It has become increasingly obvious that continued reliance on fossil fuel energy resources is unsustainable, owing to both depleting world reserves and the green house gas emissions associated with their use. Therefore, there are vigorous research initiatives aimed at developing alternative renewable and potentially carbon neutral solid, liquid and gaseous biofuels as alternative energy resources. However, alternate energy resources akin to first generation biofuels derived from terrestrial crops such as sugarcane, sugar beet, maize and rapeseed place an enormous strain on world food markets, contribute to water shortages and precipitate the destruction of the world's forests. Second generation biofuels derived from lignocellulosic agriculture and forest residues and from non-food crop feedstocks address some of the above problems; however there is concern over competing land use or required land use changes. Therefore, based on current knowledge and technology projections, third generation biofuels specifically derived from microalgae are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first and second generation biofuels. Microalgae are photosynthetic microorganisms with simple growing requirements (light, sugars, CO 2 , N, P, and K) that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and valuable co-products. This study reviewed the technologies underpinning microalgae-to-biofuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products. It also reviewed the synergistic coupling of microalgae propagation with carbon sequestration and wastewater treatment potential for mitigation of environmental impacts associated with energy conversion and utilisation. It was found that, whereas there are outstanding issues related to photosynthetic efficiencies and biomass output, microalgae-derived biofuels could progressively substitute a significant proportion of the fossil fuels required to meet the growing energy demand.

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Biofuels from microalgae—A review of technologies for production, processing, and extractions of biofuels and co-products

Dual role of microalgae: Phycoremediation of domestic wastewater and biomass production for sustainable biofuels production

Organization for Economic Co-Operation and Development (OECD).

Application of response surface methodology and artificial neural network methods in modelling and optimization of biosorption process.

An eco-friendly process: predictive modelling of copper adsorption from aqueous solution on Spirulina platensis.

In this study, Arthrospira platensis biomass was employed as a biosorbent for the removal of methylene blue (MB) dye from aqueous solutions. The kinetic data were better described by the pseudo-second order model and equilibrium was established within 60–120 min. The intra-particle diffusion was not the only rate-limiting step and film diffusion might contribute to MB biosorption process. The increase of temperature from 298 to 318 K caused a decrease of biosorption capacity. The Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models described well the experimental equilibrium data at all studied temperatures. The maximum monolayer adsorption capacity (qmax) was 312.5 mg MB/g at 298 K and pH 7.5. According to the results of the thermodynamic analysis and the release of exchangeable cations from the biomass surface, physical sorption and ion exchange were the dominant mechanisms of MB biosorption at lower temperature. Methanol esterification of the dried biomass showed the involvement of carboxyl functional groups in MB chemisorption. The thermodynamic parameters indicated that MB biosorption onto A. platensis was a spontaneous, favorable and exothermic process. The biosorption results showed that A. platensis could be employed as an efficient and eco-friendly biosorbent for the removal of cationic dyes.

Abuzer Çelekli

Papers

An eco-friendly process: predictive modelling of copper adsorption from aqueous solution on Spirulina platensis.

Biosorption of methylene blue onto Arthrospira platensis biomass: kinetic, equilibrium and thermodynamic studies

Sorption equilibrium, kinetic, thermodynamic, and desorption studies of Reactive Red 120 on Chara contraria

Prediction of removal efficiency of Lanaset Red G on walnut husk using artificial neural network model

Bio-sorption of cadmium and nickel ions using Spirulina platensis: Kinetic and equilibrium studies