Atakan Ongen

Removal of astrazon red 6B from aqueous solution using waste tea and spent tea bag

ABSTRACTThis study aimed to remove basic dye (astrazon red 6B (AR)) from liquid environment by adsorption. For this purpose, batch experiments were performed using spent tea leaves (TL) and tea bags (TB) as adsorbents due to their low costs. Adsorption experiments were carried out for different initial concentrations (25–200 mg/L), different pH values (pH 2–10), and different adsorbent amounts (0.25–2 g/L) of solution. Equilibrium sorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption data fitted well to the Freundlich isotherm for TL and Langmuir isotherm for TB. Two kinetic models, pseudo-first order and pseudo-second order, were employed to describe the adsorption mechanism. According to the results of the analysis, the pseudo-second-order equation was determined to be the best model to describe the adsorption behavior for both adsorbents with the determination factor R2 ⩾ 0.92. The results prove...

Adsorption of Astrazon Blue FGRL onto sepiolite from aqueous solutions

Abstract In this study, adsorption of Astrazon Blue FGRL on sepiolite (meerschaum) from aqueous solution was investigated using different parameters like initial dye concentration, temperature, contact time and solution pH. The obtained results were then compared for all the parameters. At the end of batch adsorption studies, the equilibrium time, optimum pH and temperature were 90 min, 7 pH and 293 K, respectively. Adsorption isotherm of Astrazon Blue FGRL on sepiolite (meerschaum) was determined and correlated with common isotherm equations such as Langmuir and Freundlich models. The Freundlich model (r 2 > 0.98) appeared to fit the isotherm data better than the Langmuir model (r 2 0.99), through the first order kinetic model did not adequately fit the experiment values (r 2 < 0.99). SEM, XRD and FT-IR spectrum analyses were carried out. The obtained results showed that Sepiolite (meerschaum) can be an al...

An evaluation of tannery industry wastewater treatment sludge gasification by artificial neural network modeling.

This paper reports on the calorific value of synthetic gas (syngas) produced by gasification of dewatered sludge derived from treatment of tannery wastewater. Proximate and ultimate analyses of samples were performed. Thermochemical conversion alters the chemical structure of the waste. Dried air was used as a gasification agent at varying flow rates, which allowed the feedstock to be quickly converted into gas by means of different heterogeneous reactions. A lab-scale updraft fixed-bed steel reactor was used for thermochemical conversion of sludge samples. Artificial neural network (ANN) modeling techniques were used to observe variations in the syngas related to operational conditions. Modeled outputs showed that temporal changes of model predictions were in close accordance with real values. Correlation coefficients (r) showed that the ANN used in this study gave results with high sensitivity.

Sustainable technologies for recycling and reuse: an overview

Recycling and reuse of water, air and soil pollutants, and wastes has been an emerging issue during the recent decade to protect natural resources and the environment (Corder et al. 2015; Colling et al. 2016). A number of national and international environmental programs and projects have been increasingly performed. The most recent outcomes of those projects/research have been published referring to mostly favor sustainable technologies for recycling and reuse of various resources that include energy recovery from organic fraction of municipal solid wastes (Cesaro et al. 2016), from food wastes (Karmee 2016), from wastewater treatment plant sludge (Batstone et al. 2015; ColmenarSantos et al. 2016), compost recovery from organic fraction of municipal solid waste (Cesaro et al. 2015), and fertilizers from wastewater (Hukari et al. 2016; Puchongkawarin et al. 2015; Shepherd et al. 2016). Various industrial wastes have been recycled to produce new products or reuse in the process purposes such as vehicle recycling processes (Li et al. 2016), recycling schemes for waste dry batteries (Lin and Chiu 2015), of waste aggregate in cement bound mixtures for road pavement bases and sub-base (Pasetto and Baldo 2016), of waste automotive laminated glass and valorization of polyvinyl butyral (Swain et al. 2015), of blast furnace sludge (Drobíková et al. 2016), and recycling of electronic wastes (Awasthi et al. 2016). Besides advanced treatment technologies among which membranes are the common ones, have been applied for recycling and reuse of urban (Bunani et al. 2013) and industrial wastewaters (Zheng et al. 2015). Additionally, valorization of renewable energy sources has been a pioneering recycling and reuse sector (Byrnes et al. 2016; Sahoo 2016) that is somewhat discussed for not being green (Keramitsoglou et al. 2016) and causing environmental impact (Sokka et al. 2016). This special issue is composed of a number of scientific works presented at the 2 International Conference on Recycling and Reuse, held on 4–6 June 2014 in Istanbul, Turkey. The biennial Conference was jointly organized by Bogazici University, Environmental Sciences Institute and Istanbul University, Environmental Engineering Department, Turkey. The purpose of the Conference was to provide an advanced platform for researchers and practitioners to exchange emerging ideas and to investigate key issues on whole and progressive aspects of recycling and reuse. The Conference program included a wide spectrum of important topics in recycling and reuse concerns of wastewaters and wastes, advanced wastewater treatment, and membrane technologies for recycling and reuse. A total number of 90 oral and 155 poster presentations were given in the topics of advanced oxidation technologies, waste reduction, water and wastewater management, solid waste treatment and management, hazardous waste management, resource use, renewable energy technologies, current and future recycling markets, public health issues, and legislations and policies of recycling and reuse. This special issue, specifically named BSustainable Technologies for Recycling and Reuse^ includes 4 papers that were selected among 25 invited papers submitted to an essential peer-review process. Three of the accepted papers present examples for removal of emerging pollutants using different advanced treatment options before reuse, and the other gives a case study on mercury containing substances flow in Turkey that would be a good example for policy decision support in developing countries as well. The guest editors expect that this issue should provide an overview of recent works done in BRecycling and Reuse^ fields and fulfills scientific gaps to provide an important contribution to scientific and technological communities. Responsible editor: Philippe Garrigues

Thermal treatment of fleshing residue for producing syngas

In this paper, characteristics of syngas from the pyrolysis and gasification of tannery industry fleshing residues has been investigated. Pyrolysis and gasification behaviour were evaluated in terms of syngas composition and total energy production. Dried air and pure oxygen (99%) were used as gasification agents. Experiments were also performed in oxygen-free media. H2, CO and CH4 levels in producer gas were analysed and calorific values were calculated. Besides, weight and volume reductions during each experiment were reported. Dried air flow varied between 0.05 and 0.5 L/min during experiments. Syngas composition with higher calorific value was achieved between 0.1–0.2 L/min. It was determined that calorific values decreased related to the decrease in volume percentages of H2, CO and CH4 over 0.2 L/min gas flow. According to the statistical analysis, gasification agent had an important role in gasification performance. Average calorific value, achieved by pure oxygen, was higher than the value achieved by dried air. The lowest efficiency was achieved in oxygen-free media.

Ecological Footprint Calculation

Ecological footprint is a method that was created to calculate the load for nature of a specific population, and it also calculates the biological effective and water-containing areas which are required to obtain renewable sources for the use of people. The data obtained by the ecological footprint resource accounting provides guidance for strategic decisions on resource management. Many studies exist in the web area in order to calculate the ecological footprint automatically after entering the data. In this study, the questions in a web site were asked to people living in Istanbul in different age intervals. It was observed that the percentages of the components constituting the ecological footprints calculated for three different age ranges (three different age ranges between individuals aged 50 and below) varied according to the age ranges. In addition, the values of ecological footprints according to the education and income levels were examined for the male and the female individuals. For all the age ranges, it can be said that the ecological footprints of individuals with high economic income are higher than those with low economic income. Also, the ecological footprint of the males of the same income level is higher than the ecological footprints of the females.

An Assessment of Pyrolysis Process for the Treatment of Agricultural and Forest Wastes

As a result of social and economic activities of people, materials that completed useful life that should be removed from the environment we live in are classified as waste. Nowadays, except for local uses (burning, warming, etc.), there are few uses for general purposes (alternative fuel, etc.). Energy usage and waste amount are increasing rapidly with the increase of the population in the world and the development of industry and technology. Control of energy consumption and waste is crucial for a sustainable future. In this study, the use of pyrolysis for agriculture and forest wastes was investigated based on the literature. For this purpose, many studies on pyrolysis of organic wastes such as agriculture and forest wastes have been compiled and presented on a common basis. The methods followed in the selected studies are examined and given in the form of tables under the common headings in order that different researchers can reach easily. It has been generally agreed that the pyrolysis process, which is considered as an alternative waste management method, is an energy and environmentally friendly application for waste and that this application can be used to reduce waste and recycle waste.

The relationship between income level and CFP level of the provinces in Turkey: a case study

This study determines the distribution of carbon footprint values (CFP) in Turkey by income levels, gender, age group, provinces where people live and the geographical regions of these provinces. In addition, % distribution of human activities which lead to CFP (food, travel, home, stuff) has been analysed. The carbon emission values assessed in this study have been compared with annual carbon emission distributions of various countries. In comparison by income levels, it was observed that mainly consumption-based usages (48%) take part in spending of people in the lowest income section while travel costs (42%) of people having high income have a significant contribution to CFP values. In assessment by age groups, it was observed that the highest CFP value is obtained by those aged 40 or older (in average; 17.1 tons CO2 per capita). In assessment of CFP values on the basis of geographical region and province, it was seen that high CFP values which result from the fuel type used for heating in eastern regions of Turkey replace CFP values related to transportation in western parts. In Turkey, annual carbon emission value is 15.1 tons CO2 per capita in average. This value is similar to annual carbon emission per capita of European countries such as Spain, France.

Composition and energy potential of industrial sludge derived synthetic gas

The study focused on the synthetic gas formation and gasification efficiency of an industrial sludge. Optimum conditions for gasification were determined and content of synthetic gas was investigated. Gasification is a partial oxidation process whereby a carbon source such as coal, natural gas or biomass, is broken down into carbon monoxide and hydrogen, plus carbon dioxide and possibly hydrocarbon molecules such as methane. It is reported that during the gasification process, all of the useful molecules which produce energy when burned are separated from the unwanted parts of the organic matter such as soot, tar, and ash. Therefore, this process is much cleaner than combustion process. Gasification studies over 700°C produced a synthetic gas that involved 20%-30% CO, 30%-40% H2 and 5%-15% CH4 by volume. Calorific values of 2000 kcal/m3 in average and maximum 3000 kcal/m3 were achieved by gasification both with dried air and pure oxygen as gasification agents.

The 2nd International Conference on Recycling and Reuse, held on June 4–6, 2014, in Istanbul, Turkey

This special issue of the Desalination and Water Treatment Journal is dedicated to the 2nd International Conference on Recycling and Reuse, held on 4–6 June 2014 in Istanbul, Turkey. This international conference was jointly organized by Boğaziçi University, Environmental Sciences Institute and Istanbul University, Environmental Engineering Department, Turkey. The purpose of the conference was to provide an excellent platform for researchers and practitioners to exchange emerging ideas and investigate key issues such as: