Assessment of organizational carbon footprints in a denim-washing company: a systematic approach to indirect non-energy emissions.

As stated in the 2016 Paris Agreement, concerns about global climate change and carbon emissions have increased, and organizations, in particular, have embarked on an annual measurement process to estimate their contribution to global climate change. Carbon footprint, one of the measurement methods, is a widely applied tool to assess the environmental impact of organizations. This study presents a real case study of a denim-washing company's activities based on ISO standard calculation methods of greenhouse gas emissions. Accordingly, the annual carbon footprint of the denim-washing company was 2482.09 tCO2e for the year 2021 in total for the overall carbon footprint. Direct emission was calculated at 1575.75 tCO2e, indirect energy-related emission at 798.09 tCO2e, and indirect non-energy-related emission at 108.25 tCO2e. The highest CO2 emissions are related to heating from greenhouse gas direct emission sources, followed by purchased electricity consumption, and the lowest CO2 emissions are related to fire-CO2 tube storage. In conclusion, this study is particular in that it analyzes not only the specific processes of a denim-washing company but also the overall organizational carbon footprint calculation, assesses the importance of indirect non-energy in the total carbon footprint, and evaluates the calculation findings with sector-specific mitigation strategies.

Kinetic, isotherm modeling analyses of the adsorption of phenol on activated carbon/alginate composites.

The present study aimed to synthesize calcium alginate-commercial activated carbon composite beads (CA-AC) and calcium alginate-walnut shell biochar composite beads (CA-WSB) using activated carbon (AC), walnut shell biochar (WSB), and to apply its efficiency in phenol removal. The synthesized samples were characterized by energy-dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF) spectrometry.The Brunauer, Emmett, and Teller (BET) method was used to obtain information about the samples' surface area and pore size. The kinetic model of phenol fitted well to the pseudo-second-order kinetic model. The isotherm model of phenol fitted well to the Langmuir isotherm model compared with other models. The maximum adsorption capacity was 76.92, 0.419, 8.130 1.375 mg/g for AC, WSB, CA-AC, CA-WSB.

Pyrolysis is among the disposal methods applied to reduce the impact of agricultural and animal wastes on the environment and human health and to ensure their management. Biochars are widely used alternative adsorbent for the removal of pollutants from wastewater. No published work has been on the walnut shell biochar (WSB) encapsulated alginate hydrogel bead for the phenol adsorption from an aqueous solution. The novelty of this study was to compare the adsorption capacity, and removal efficiencies of calcium alginate-commercial activated carbon composite beads (CA-AC) and calcium alginate-biochar composite beads (CA-WSB) prepared from walnut shells by pyrolysis and investigated the adsorption performance for phenol removal.

Leaching Performance and Zinc Ions Removal from Industrial Slag Leachate Using Natural and Biochar Walnut Shell.

This study aims to investigate leaching characteristics of zinc slag according to leaching tests, including; TCLP (Toxicity Characteristic Leaching Procedure), SPLP (Synthetic Precipitation Leaching Procedure), ASTM-D3987 (American Society for Testing and Materials), and TS EN-12457-4 (Turkish Standards Institute) tests methods. The present study describes the adsorption potential of natural and biochar walnut shells for removing ions from the zinc leachate. TCLP leachate, with a value of 38.575 mg/L, has a high zinc (Zn+2) concentration compared to other methods. Therefore, TCLP leachate was used in the adsorption experiments. Adsorption experiments were carried out at different adsorbent dosages, pH values, and contact time conditions. In the dosage study, the highest removal efficiency was obtained as 84% and 92% in natural and biochar walnut shell adsorbents, respectively. As a result of pH study, it was observed that adsorption under alkaline conditions had a much higher removal efficiency. Moreover, adsorption studies performed against contact time were applied to four different kinetic models and both adsorbents were found to be fit with the pseudo-second-order model. This kinetic model showed that the Zn+2 adsorption mechanism of natural and biochar walnut shells is chemical adsorption. With this study, it was shown that a very high 96% zinc removal can be achieved under optimum adsorption conditions. This may be the first study of zinc removal after leaching from industrial slag in the literature. This study has shown that high removal efficiencies can be obtained by an economical adsorbent.

The use of NARX neural network for modeling of adsorption of zinc ions using activated almond shell as a potential biosorbent.

In this study, nonlinear autoregressive model processes with exogenous input (NARX) are applied for the prediction of percentage adsorption efficiency for the removal of zinc ions from wastewater by activated almond shell. The effect of operational parameters such as pH, dosage, particle size and initial metal ions concentration are studied to optimize the conditions for maximum removal of zinc ions. The model is first developed using a two layer NARX network. A comparison between the model results and experimental data showed that the NARX model is able to predict the removal of zinc ions from wastewater. The outcomes of suggested NARX modeling were then compared to batch experimental studies. The results show that activated almond shell is an efficient sorbent and NARX network, which is easy to implement and is able to model the batch experimental system.

Statistical evaluation and optimization of factors affecting the leaching performance of copper flotation waste.

Copper flotation waste is an industrial by-product material produced from the process of manufacturing copper. The main concern with respect to landfilling of copper flotation waste is the release of elements (e.g., salts and heavy metals) when in contact with water, that is, leaching. Copper flotation waste generally contains a significant amount of Cu together with trace elements of other toxic metals, such as Zn, Co, and Pb. The release of heavy metals into the environment has resulted in a number of environmental problems. The aim of this study is to investigate the leaching characteristics of copper flotation waste by use of the Box-Behnken experimental design approach. In order to obtain the optimized condition of leachability, a second-order model was examined. The best leaching conditions achieved were as follows: pH = 9, stirring time = 5 min, and temperature = 41.5 °C.

Adsorption of basic dye from wastewater using raw and activated red mud.

Red mud, an industrial by-product generated during the processing of bauxite ore, was investigated as an inexpensive and effective adsorbent for the adsorption of methylene blue from aqueous solution. Chemical and heat treatments were applied to the raw red mud. The effects of contact time, adsorbent amount, pH, temperature and initial dye concentration were investigated. The adsorption isotherm and kinetics of the raw and activated red mud were studied. Freundlich, Temkin and Dubinin-Radushkevich isotherms were obtained using concentrations of methylene blue ranging from 10 to 70 mg/L. The results indicated that the Dubinin-Radushkevich model provides the best correlation of the experimental data. The adsorption rate data were analysed according to the pseudo-first order kinetic, pseudo-second order kinetic, intraparticle diffusion kinetic and Elovich kinetic models. The pseudo-second order kinetic was the best fit kinetic model for the experimental data.

A comparison of the properties of natural clinoptilolites and their ion-exchange capacities for silver removal.

The aim of the present study is to investigate the removal of silver ions from aqueous solutions using natural clinoptilolites collected from Cankiri-Corum and Manisa-Gördes regions of Turkey. The optimum conditions for adsorption/ion exchange by using a batch method were evaluated by changing various parameters such as particle size, contact time, initial pH of the solution, adsorbent amount, initial metal concentration and acidic treatment. The Langmuir, Freundlich and Temkin adsorption isotherm equations were derived form the basic empirical equations, and used for calculation of adsorption parameters. The equilibrium data fit well the Freundlich and Langmuir isotherm. The adsorption capacities of Cankiri-Corum and Manisa-Gördes clinoptilolites as obtained from Langmuir isotherm were found to be 31.44 and 22.57 mg/g. The adsorption kinetic rates and metal recoveries were estimated by pseudo-first order, second order and intra-particle models.

Use of fly ash, phosphogypsum and red mud as a liner material for the disposal of hazardous zinc leach residue waste.

Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The release of large quantities of heavy metals into the environment has resulted in a number of environmental problems. The present study investigated the safe disposal of the zinc leach residue waste using industrial residues such as fly ash, phosphogypsum and red mud. In the study, leachability of heavy metals from the zinc leach residue has been evaluated by mine water leaching procedure (MWLP) and toxicity characteristic leaching procedure (TCLP). Zinc removal from leachate was studied using fly ash, phosphogypsum and red mud. The adsorption capacities and adsorption efficiencies were determined. The adsorption rate data was analyzed according to the pseudo-second-order kinetic, Elovich kinetic and intra-particle diffusion kinetic models. The pseudo-second-order kinetic was the best fit kinetic model for the experimental data. The results show that addition of fly ash, phosphogypsum and red mud to the zinc leach residue drastically reduces the heavy metal content in the leachate and could be used as liner materials.

Leaching behaviour and mechanical properties of copper flotation waste in stabilized/solidified products.

This research describes the investigation of a cement-based solidification/stabilization process for the safe disposal of copper flotation waste and the effect on cement properties of the addition of copper flotation waste (CW) and clinoptilolite (C). In addition to the reference mixture, 17 different mixtures were prepared using different proportions of CW and C. Physical properties such as setting time, specific surface area and compressive strength were determined and compared to a reference mixture and Turkish standards (TS). Different mixtures with the copper flotation waste portion ranging from 2.5 to 12.5% by weight of the mixture were tested for copper leachability. The results show that as cement replacement materials especially clinoptilolite had clear effects on the mechanical properties. Substitution of 5% copper flotation waste for Portland cement gave a similar strength performance to the reference mixture. Higher copper flotation waste addition such as 12.5% replacement yielded lower strength values. As a result, copper flotation waste and clinoptilolite can be used as cementitious materials, and copper flotation waste also can be safely stabilized/solidified in a cement-based solidification/stabilization system.

Municipal solid waste management strategies in Turkey.

Municipal solid waste (MSW) is a major environmental problem in Turkey, as in many developing countries. Problems associated with municipal solid waste are difficult to address, but efforts towards more efficient collection and transportation and environmentally acceptable waste disposal continue in Turkey. Although strict regulations on the management of solid waste are in place, primitive disposal methods such as open dumping and discharge into surface water have been used in various parts of Turkey. This study presents a brief history of the legislative trends in Turkey for MSW management. The study also presents the MSW responsibility and management structure together with the present situation of generation, composition, recycling, and treatment. The results show that approximately 25 million ton of MSW are generated annually in Turkey. About 77% of the population receives MSW services. In spite of efforts to change open dumping areas into sanitary landfills and to build modern recycling and composting facilities, Turkey still has over 2000 open dumps.

Immobilization of copper flotation waste using red mud and clinoptilolite.

The flash smelting process has been used in the copper industry for a number of years and has replaced most of the reverberatory applications, known as conventional copper smelting processes. Copper smelters produce large amounts of copper slag or copper flotation waste and the dumping of these quantities of copper slag causes economic, environmental and space problems. The aim of this study was to perform a laboratory investigation to assess the feasibility of immobilizing the heavy metals contained in copper flotation waste. For this purpose, samples of copper flotation waste were immobilized with relatively small proportions of red mud and large proportions of clinoptilolite. The results of laboratory leaching demonstrate that addition of red mud and clinoptilolite to the copper flotation waste drastically reduced the heavy metal content in the effluent and the red mud performed better than clinoptilolite. This study also compared the leaching behaviour of metals in copper flotation waste by short-time extraction tests such as the toxicity characteristic leaching procedure (TCLP), deionized water (DI) and field leach test (FLT). The results of leach tests showed that the results of the FLT and DI methods were close and generally lower than those of the TCLP methods.

Treatment of copper industry waste and production of sintered glass-ceramic.

Copper waste is iron-rich hazardous waste containing heavy metals such as Cu, Zn, Co, Pb. The results of leaching tests show that the concentration of these elements exceeds the Turkish and EPA regulatory limits. Consequently, this waste cannot be disposed of in its present form and therefore requires treatment to stabilize it or make it inert prior to disposal. Vitrification was selected as the technology for the treatment of the toxic waste under investigation. During the vitrification process significant amounts of the toxic organic and inorganic chemical compounds could be destroyed, and at the same time, the metal species are immobilized as they become an integral part of the glass matrix. The copper flotation waste samples used in this research were obtained from the Black Sea Copper Works of Samsun, Turkey. The samples were vitrified after being mixed with other inorganic waste and materials. The copper flotation waste and their glass-ceramic products were characterized by X-ray analysis (XRD), scanning electron microscopy and by the toxicity characteristic leaching procedure test. The products showed very good chemical durability. The glass-ceramics fabricated at 850 degrees C/2 h have a large application potential especially as construction and building materials.

Leaching characteristics of copper flotation waste before and after vitrification.

Copper flotation waste from copper production using a pyrometallurgical process contains toxic metals such as Cu, Zn, Co and Pb. Because of the presence of trace amounts of these highly toxic metals, copper flotation waste contributes to environmental pollution. In this study, the leaching characteristics of copper flotation waste from the Black Sea Copper Works in Samsun, Turkey have been investigated before and after vitrification. Samples obtained from the factory were subjected to toxicity tests such as the extraction procedure toxicity test (EP Tox), the toxicity characteristic leaching procedure (TCLP) and the "method A" extraction procedure of the American Society of Testing and Materials. The leaching tests showed that the content of some elements in the waste before vitrification exceed the regulatory limits and cannot be disposed of in the present form. Therefore, a stabilization or inertization treatment is necessary prior to disposal. Vitrification was found to stabilize heavy metals in the copper flotation waste successfully and leaching of these metals was largely reduced. Therefore, vitrification can be an acceptable method for disposal of copper flotation waste.

Production of brown and black pigments by using flotation waste from copper slag.

One of the major problems in copper-producing countries is the treatment of the large amount of copper slag or copper flotation waste generated from copper slag which contains significant amounts of heavy metals such as Cu, Zn, Pb and Co. Dumping or disposal of such large quantities of flotation waste from copper slag causes environmental and space problems. In this study, the treatment of flotation waste from copper slag by a thermal method and its use as an iron source in the production of inorganic brown and black pigments that are used in the ceramic industry were investigated. The pigments were produced by calcining different amounts of flotation waste and chromite, Cr2O3, ZnO and CoO mixtures. The pigments obtained were added to transparent ceramic glazes and porcelainized tile bodies. Their colours were defined by L*a*b* measurements with a spectrophotometer. The results showed that flotation waste from copper slag could be used as an iron source to produce brown and black pigments in both ceramic body and glazes.