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Continuous Process Design Model Simulation for the Anaerobic Digestion of Vegetable Oil Wastewater
Nweke Chinenyenwa Nkeiruka,
Nwabanne Joseph Tagbo
Issue:
Volume 3, Issue 5, October 2014
Pages:
209-216
Received:
11 September 2014
Accepted:
23 September 2014
Published:
20 October 2014
Abstract: Simulation of a mathematical model for the design of steady-state continuous reactors required for the anaerobic digestion of wastewaters was carried out. This was obtained so as to make the design of continuous stirred tank reactor (CSTR) that would be used for the anaerobic digestion of vegetable oil wastewater (VOW) possible. The model considered the kinetics of the process which has been previously determined during the batch digestion of the wastewater. The hydraulic retention time (HRT) and solid retention time (SRT) which are important parameters required for the design were estimated by varying different model parameters such as efficiency of reactor, influent substrate concentration (So) and biomass concentration (X) at various food-microorganism ratios (F/M). The HRT was calculated for different reactor efficiency (E) varying in the range of 70-95% at a constant influent substrate concentration. It was observed that the HRT increased with increase in efficiency ranging between 1.10 to 7.06 days. HRT also increased as the biomass concentration increased. SRT at constant influent substrate concentration and biomass concentration were observed to increase as the reactor efficiency increased. The effect of different substrate concentration on HRT to attain a targeted efficiency in the CSTR under steady state condition was also studied. It was observed that HRT linearly increased with increase in influent substrate concentration at constant reactor efficiency and biomass concentration. HRT also increased with decrease in biomass concentration and constant reactor efficiency for a particular substrate concentration. There was also an increase in HRT as reactor efficiency increased at constant biomass and influent substrate concentrations. SRT calculated at E1 (70%) and E2 (80%) efficiencies were observed to decrease with increase in influent substrate concentration. As the efficiencies of the reactor increased, SRT was also observed to increase. With the information obtained from the model simulation, a continuous stirred tank reactor that would treat VOW by anaerobic digestion could be designed.
Abstract: Simulation of a mathematical model for the design of steady-state continuous reactors required for the anaerobic digestion of wastewaters was carried out. This was obtained so as to make the design of continuous stirred tank reactor (CSTR) that would be used for the anaerobic digestion of vegetable oil wastewater (VOW) possible. The model considere...
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Possibilities for Achieving the Vision of Near Net Zero Emission in Building Sector in Bosnia and Herzegovina
Sandra Martinovic,
Rejhana Muhamedagic,
Azrudin Husika
Issue:
Volume 3, Issue 5, October 2014
Pages:
217-224
Received:
16 September 2014
Accepted:
5 October 2014
Published:
20 October 2014
Abstract: Increase of greenhouse gases concentration in the atmosphere, mainly carbon dioxide, which leads to global warming, indicates the need to take actions to reduce use of energy from carbon sources. The building sector is the largest consumer of energy, and thereby the largest emitter of greenhouse gases. In this paper the possibilities of achieving "near net zero emission" vision, in the residential sector, by the year 2050, were analysed. The necessary policies and technical energy efficiency measures were analysed, that could be applied in the building sector in Bosnia and Herzegovina by 2050. Large amount of energy is used for space heating and hot water, mainly from fossil fuels, which significantly contributes to air pollution and global warming. Specific energy consumption for space heating in Bosnia and Herzegovina is several times higher than in EU countries with the similar climate conditions. Therefore, it is necessary to reduce energy consumption significantly, ie to increase energy efficiency. It is also necessary to deploy the potential of renewable energy use in buildings and to use buildings as energy producers. In this way, in the long term, energy costs in buildings would be significantly reduced, as well as dependence on energy imports and the need for building of new capacities for energy generation. From other side, employment would be increased while emissions of pollutants and greenhouse gases would be reduced. In this paper, due to the availability of reliable data on energy consumption for the Sarajevo Canton, the necessary policies and measures to promote energy efficiency were analysed, that could be applied in the residential sector in the Sarajevo Canton.
Abstract: Increase of greenhouse gases concentration in the atmosphere, mainly carbon dioxide, which leads to global warming, indicates the need to take actions to reduce use of energy from carbon sources. The building sector is the largest consumer of energy, and thereby the largest emitter of greenhouse gases. In this paper the possibilities of achieving "...
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Characteristics of Diverted Solid Waste in Kumasi: A Ghanaian City
Adam Wahabu,
Sampson Oduro-Kwarteng,
Isaac Monney,
Prosper Kotoka
Issue:
Volume 3, Issue 5, October 2014
Pages:
225-231
Received:
20 September 2014
Accepted:
5 October 2014
Published:
20 October 2014
Abstract: Waste diversion from landfills has generally been neglected in the developing world despite its potential to prolong the lifespan of landfills and generate revenues. This study aims at characterizing diverted solid waste fractions at communal collection points in seven communities and determining the trends in landfilled solid waste due to the Pay-As-You-Throw (PAYT) mechanism. It is based on quantitative measurements of diverted waste by informal waste pickers at communal collection points in seven communities in the Kumasi metropolis and analysis of landfilled waste records prior to and after the introduction of the PAYT mechanism. The study shows a daily diversion rate of 19.4±9.2kg per informal waste picker per day with no statistically significant difference (p = 0.29). This constitutes just 0.5w/w% of the total waste stream at communal collection points. The diverted waste is dominated by plastics (50%) and metals (29%). Generally, the diverted waste quantities are hugely dependent on the storage capacities of the informal waste pickers while the types of recovered items depend on readily available market. The introduction of the PAYT system, as observed from the study, immediately caused a decline (28%) in waste disposed of at communal collection points but steadily appreciated with time (26% and 13% consecutive reductions in subsequent years). The study recommends support for the informal sector, Public-Private Partnerships for waste recycling and intensive public education on PAYT mechanism prior to and after its introduction.
Abstract: Waste diversion from landfills has generally been neglected in the developing world despite its potential to prolong the lifespan of landfills and generate revenues. This study aims at characterizing diverted solid waste fractions at communal collection points in seven communities and determining the trends in landfilled solid waste due to the Pay-...
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Water Quality Assessment of an Industrial Zone Polluted Aquatic Body in Dhaka, Bangladesh
Mahmuda Akter,
Tajuddin Sikder,
A. K. M. Atique Ullah
Issue:
Volume 3, Issue 5, October 2014
Pages:
232-237
Received:
24 September 2014
Accepted:
13 October 2014
Published:
30 October 2014
Abstract: Water quality in the aquatic body of Dhaka Export Processing Zone (DEPZ) area was studied on the basis of some physiochemical parameters and heavy metal concentrations. Physiochemical parameters like pH, Electrical Conductivity (EC), Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and concentrations of some heavy metals like As, Cd, Cu, Co, Cr, Fe, Mn, Ni, Pb, Hg and Zn were measured. Among different physiochemical parameters, pH, TDS and EC were found within the range. The range of pH for all of the samples was found from 7.1 to 8.17 and 120 to 450 mg/L for TDS. The Values of EC were found from 90 to 300 µs cm-1. For pH, EC and TDS, though the ranges were within the limits but there was an increasing trend of the values was observed in every case which is highly alarming. The range of COD values was estimated from 90 to 300 mg/L and in most of the samples the values exceeded the standard range. The heavy metal containments of the surface water indicated that the concentrations of Cr, Cu, Ni, Zn, Hg and As were obtained below the permissible limit, detection by WHO, 1996. On the other hand, concentrations of Cd, Co, Fe, Pb, Mn and Hg were exceeded the permissible limits. Correlation matrix shows a significant correlation among Pb, Cu, Co, Mn and Fe. Enrichment factor shows high concentrations of Cd, Cr and Hg. Stated environmental condition is highly vulnerable for human being, that’s why this is the time to take proper steps for remediation and preventing the pollution around DEPZ water body which is directly related to the industrial emission of DEPZ.
Abstract: Water quality in the aquatic body of Dhaka Export Processing Zone (DEPZ) area was studied on the basis of some physiochemical parameters and heavy metal concentrations. Physiochemical parameters like pH, Electrical Conductivity (EC), Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and concentrations of some heavy metals like As, Cd, Cu, ...
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Testing the Degree of Biostabilization in the Refuse from Composting Plants
Antonio Gallardo Izquierdo,
Francisco José Colomer Mendoza,
Eduard Cirstea,
Natalia Edo Alcón,
Joan Esteban Altabella
Issue:
Volume 3, Issue 5, October 2014
Pages:
238-243
Received:
8 October 2014
Accepted:
21 October 2014
Published:
30 October 2014
Abstract: In composting plants, aerobic fermentation could not to be complete and therefore, the fate of unstabilyzed wastes from the compost refining, uses to be landfill. This fact provokes an extra biogas generation in landfills, which contributes to greenhouse effect. In this work, the refuse of compost refining process has been subjected to an anaerobic fermentation. For that, in order to analyze their biogas generation, three samples of different composting plants have been selected. In one of these plants, the amount of biogas generation has been considerable, which involves a not complete stabilization of biowaste in the composting process.
Abstract: In composting plants, aerobic fermentation could not to be complete and therefore, the fate of unstabilyzed wastes from the compost refining, uses to be landfill. This fact provokes an extra biogas generation in landfills, which contributes to greenhouse effect. In this work, the refuse of compost refining process has been subjected to an anaerobic...
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Conception of Ecocity with Ecological Infrastructure
Issue:
Volume 3, Issue 5, October 2014
Pages:
244-248
Received:
30 September 2014
Accepted:
23 October 2014
Published:
30 October 2014
Abstract: Wide conception of «zero» eco-buildings and of «zero» ecocities with ecological infrastructure is based on three principles: «zero» interference in the nature, «zero» consumption of consumable resources from state networks, «zero» emission of pollution. «Zero» interference in the nature is the «zero» built-up area of buildings; it includes the minimal interference to natural circulation of matter, to migrations of animals; it signifies the sensory likeness to nature (use of sensory ecology – visual, odor and sound ecology); gardening of buildings, etc. «Zero» consumption of consumable resources includes: energy economy; renewable electric and thermal energy generation; natural ventilation and air-conditioning without energy consumption; decrease of expenses for internal illumination; reduction of water consumption, etc. «Zero» emission of pollution includes «zero» life cycle of buildings, recycling of waste products, use of ecological and recycled materials, the «zero» water drain, etc. The basis of «zero» eco-buildings and ecocities creation is architectural-building ecology with ecological infrastructure (it is complex of natural resources, constructions and systems, providing support of environment of human life at all levels - from the whole country up to cities and to separate buildings). Environment of life and environments of «zero» buildings and cities must be subject to all-embracing ecologization. All-embracing ecologization is system of upbringing of ecological thinking for respective activity and for use of ecological decisions based on ecological postulates, ecological philosophy and ethics, principles of sustainable building, adoption into account ethnical and geographical traits, social-psychological and social-economical features of inhabitants in city. This ecologization is the hierarchical system (from global up to local).
Abstract: Wide conception of «zero» eco-buildings and of «zero» ecocities with ecological infrastructure is based on three principles: «zero» interference in the nature, «zero» consumption of consumable resources from state networks, «zero» emission of pollution. «Zero» interference in the nature is the «zero» built-up area of buildings; it includes the mini...
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Beneficial Reuse: A Field Trial to Remediate and a Bench-Scale Test to Revegetate Coal Seam Gas Dam Sediments from Queensland
Issue:
Volume 3, Issue 5, October 2014
Pages:
249-257
Received:
11 October 2014
Accepted:
27 October 2014
Published:
30 October 2014
Abstract: Coal seam gas (CSG) has become an increasingly common method of extracting methane from coal in Australia, with more than 20,000 wells expected to enter production by 2020. However, large quantities of “produced water” also come to the surface with gas, and these several thousand litres of water per day per well have to be managed sustainably. Furthermore, up to five percent of produced water is composed of suspended or dissolved solids, most typically present in the form of salty brines and a range of other elements, sometimes including benzene and other hydrocarbons like phenols. CSG solids therefore have a high pH and total alkalinity, and hence have elevated electrical conductivity. As a consequence, the settled solids from CSG extraction have no proven beneficial reuse value, and successful revegetation of dams and untreated sediments is limited to salt-tolerant grass species but is often impossible using any species under any condition. The purpose of this study is to investigate the remediation of CSG dam sediments from Queensland for the purposes of determining their potential beneficial reuse as “clean, usable soil” in revegetation projects. Experiment #1, a field trial conducted in the Bowen Basin, examined the impact of various additives to two different types of CSG dam sediments. Experiment #1 found that both types of sediment could be remediated, examples of which include decreases in pH from 10.0 to 7.4, chloride from 19,900mg/kg to 1,770mg/kg, cation-exchange capacity (CEC) from 23meq/100g to 4.0meq/100g, and sodium adsorption ratio (SAR) from 931meq/100g to 44meq/100g, and increases in total phosphorus from 27mg/kg to 855mg/kg and total nitrogen from 950mg/kg to 3,520mg/kg. These findings confirm that contaminated CSG sediments have beneficial reuse potential in dam decommissioning and revegetation projects. Experiment #2, a bench-scale test utilizing samples of treated sediments from Experiment #1, examined the revegetation potential of these remediated CSG sediments. Experiment #2 showed that both types of CSG dam sediment could be effectively revegetated using non-salt-tolerant grass species, while untreated sediments were not suitable for revegetation. However, the design and scale of this work need to be expanded, and variables such as sediment pH, CEC and SAR should be monitored and controlled more carefully before fully reliable conclusions can be made about the revegetation potential of treated CSG dam sediments.
Abstract: Coal seam gas (CSG) has become an increasingly common method of extracting methane from coal in Australia, with more than 20,000 wells expected to enter production by 2020. However, large quantities of “produced water” also come to the surface with gas, and these several thousand litres of water per day per well have to be managed sustainably. Furt...
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Study of the Level of Awareness of the Iraqi Society to the Impact of Climate Changes
Ahmed Hasson,
Saad KH. Mahmood Aljumaili
Issue:
Volume 3, Issue 5, October 2014
Pages:
258-262
Received:
5 October 2014
Accepted:
27 October 2014
Published:
30 October 2014
Abstract: Baghdad is a large city, warmer than surrounding areas due to the urban heat island effect. This research is to understand what Iraqi society segments thought about issues represented a tangible threat to their urban environment and lifestyle. Questions were establish what scholars, student and Architect thought about the impact of climate change and UHI. Analysis indicated that there was a moderated acceptance in society segments, students, scholars and low among the urban residents of Iraqi society that complex issue such as Urban Heat Island as part of climate change was occurring and an even lower acceptance that it was the result of human activity. Nonetheless, the low acceptance reflected a high degree of uncertainty among urban people rather than widespread open skepticism. The uncertainty among urban residents could be attributable to scientific discrepancies about causes of Urban Heat Island and the possible consequences. The results show that trust in science and scientific credibility has been undermined by these discrepancies and the perception that scientists are using climate change to pursue their own agendas. With only 52% of educated survey respondents believing that climate change and Urban Heat Island information were easy to understand, there was a clear need to reconsider communication strategies for the dissemination of scientific information in universities and institutes. Results indicate that minimal adaptive responses of Iraqi society to changes in local climate, current and past extreme changes in Iraqi urban temperature, water scarcity and dust storm seasons support results that indicate society did not prioritize Urban Heat Island imperative. Generally, well-educated community did not recognize or underestimated the short to medium term risk Urban Heat Island represented for their urban environment or lifestyles.
Abstract: Baghdad is a large city, warmer than surrounding areas due to the urban heat island effect. This research is to understand what Iraqi society segments thought about issues represented a tangible threat to their urban environment and lifestyle. Questions were establish what scholars, student and Architect thought about the impact of climate change a...
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Thermographic Modeling of Pollution of Reservoirs with Solutions NaCl
Кonstantin Bozhko,
Volodymyr Maslov,
Volodymyr Porev,
Volodymyr Timofeev,
Еvgen Venger,
Vadim Dunaevskiy,
Vitaliy Kotovskiy,
Svetlana Nazarchuk,
Mykhailo Lysenko
Issue:
Volume 3, Issue 5, October 2014
Pages:
263-266
Received:
6 October 2014
Accepted:
23 October 2014
Published:
10 November 2014
Abstract: A thermographic method for studying the dynamics of the process of pollution of the reservoirs with solutions containing salt has been approved. The method enables control over the stratification of polluted water with a contaminative solution by its thermal field, regardless of the transparency of the components of pollution. Authors have offered the analytical solution for the model of running of the spot of a pollutive solution over the bottom of the tank, which can greatly simplify calculations. The result of research is confirmation of the hypothesis of the predominant influence of the mechanism of a gravitational transfer when the reservoirs are being contaminated with salt solutions. Pollution is localized in the bottom area of a pond. The water intake for the needs of cities and towns should be performed only at surface layers of the reservoirs because many soluble contaminants concentrate in bottom layers.
Abstract: A thermographic method for studying the dynamics of the process of pollution of the reservoirs with solutions containing salt has been approved. The method enables control over the stratification of polluted water with a contaminative solution by its thermal field, regardless of the transparency of the components of pollution. Authors have offered ...
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Hydrogen Sulfide Generation Suppression by Nitrate Addition – Application to Solid Waste Landfill Site
Shumpei Kitazaki,
Kai Xiao,
Kei Nakagawa,
Tomonori Kindaichi,
Hiroshi Asakura
Issue:
Volume 3, Issue 5, October 2014
Pages:
267-274
Received:
22 October 2014
Accepted:
31 October 2014
Published:
10 November 2014
Abstract: In Japan, three deaths were reported at an inert solid waste landfill site after exposure to hydrogen sulfide (H2S) generated at the site. H2S gas is produced when sulfate-reducing bacteria (SRB) convert sulfate derived from waste gypsum board under anaerobic conditions. The recommended countermeasure is to supply oxygen by installing gas venting pipes. However, a large cost is necessary for pipe installation and the pipes are not applicable to coastal landfill sites. On the other hand, H2S generation suppression by nitrate (NO3) addition has been reported in sewage systems. In this study, in order to develop a method to suppress H2S generation by NO3 addition at a landfill site, the extent of suppression was quantitatively estimated. When NO3 reagent was added at the rate of 0.46 mmol-NO3/(L•d) into a liquid from which H2S gas was generated at the rate of 0.21 ± 0.05 mmol-H2S/(L•d), H2S generation rate was decreased to approximately 1/4 of the original rate. Although it was difficult to maintain the concentration of NO3 because it tended to disappear rapidly, the frequent addition of NO3 reagent to maintain the concentration of approximately 430 mg-NO3/L enabled us to control H2S concentration to below 1000 ppmv for one month and H2S generation rate to below 1/20 of the original rate.
Abstract: In Japan, three deaths were reported at an inert solid waste landfill site after exposure to hydrogen sulfide (H2S) generated at the site. H2S gas is produced when sulfate-reducing bacteria (SRB) convert sulfate derived from waste gypsum board under anaerobic conditions. The recommended countermeasure is to supply oxygen by installing gas venting p...
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Determination and Sorting of Asbestos-Containing Material by Visual Observation
Hiroshi Asakura,
Mikio Kawasaki,
Kazuyuki Suzuki,
Kei Nakagawa,
Yoichi Watanabe
Issue:
Volume 3, Issue 5, October 2014
Pages:
275-282
Received:
31 October 2014
Accepted:
5 November 2014
Published:
20 November 2014
Abstract: A rapid method for the determination of asbestos fiber at an intermediate treatment facility for construction and demolition waste (CDW) is required. Although the rapid method which involves visual observation has been developed, the determination accuracy and time are unknown. The purpose of this study was to determine the identification rate of asbestos-containing material (ACM: > 0.1w%), the time required for asbestos fiber determination by visual observation, and the asbestos content in CDW. After participating in a short training course for ACM determination, persons who did not have any knowledge of asbestos fiber determination were able to determine ACM in CDW by visual observation. Using the results of visual observation, an ACM sorting model was formulated. The model enabled simulation of asbestos content after sorting by inputting asbestos content distribution into CDW before sorting. However, 0.35 w% of asbestos still remained in the non-ACM fraction, i.e., the content was > 0.1 w%. The relationship between the number of sorters and the total sorting time for disaster waste from the Great East Japan Earthquake was presented. It was found that a very long time and a large number of people were required for sorting.
Abstract: A rapid method for the determination of asbestos fiber at an intermediate treatment facility for construction and demolition waste (CDW) is required. Although the rapid method which involves visual observation has been developed, the determination accuracy and time are unknown. The purpose of this study was to determine the identification rate of a...
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Effect of Sewage Water Irrigation on Soil Properties and Evaluation of the Accumulation of Elements in Grass Crop in Mysore City, Karnataka, India
Mohammed A. Alghobar,
Lathamani Ramachandra,
Sidduraiah Suresha
Issue:
Volume 3, Issue 5, October 2014
Pages:
283-291
Received:
1 November 2014
Accepted:
12 November 2014
Published:
20 November 2014
Abstract: Use of sewage water for irrigation improved chemical properties and fertility status in soil. Sewage water contains elements essential for plant growth and also contains heavy metals which may be toxic for animals if their concentration exceeds than permissible limit. To monitor this situation, a survey was conducted to ascertain the addition of heavy metals into agricultural fields through sewage water irrigation for grass crop in the farmlands of selected areas of Vidyaranyapuram in Mysore city. The results indicated that in sewage water the permissible amounts of total N, total P and potassium which are considered essential nutrients for productivity levels (grass growth) and soil fertility. The concentrations of heavy metals in the sewage water were in the proposed Food and Agriculture Organization range. The analysis showed that in soil concentration the irrigation with sewage water (SW) and treated sewage water (TSW) induces significant (P<0.05) decrease of soil pH when compared to MW and control treatment GW. The SW and TSW affect significantly the EC Indeed, in comparison with groundwater (GW), EC is greater with SW and TSW treatment. For Major elements contents and fertilizer as observed in the irrigation with SW led to a significant increase of Ca, Na, N, P, K and SO4 in comparison with the control ground water (GW). For Cl, in irrigation with SW has no effect on the Cl of soil. For heavy metals in comparison to the standard, the SW has no a significant (P < 0.05) effect in all elements except significant increase was noticed for Fe. In the grass, our investigation showed that irrigation with SW reuse led to a significant increase (P< 0.05) of N, P, K, Ca, Mg and Na contents. Heavy metals shown in grass irrigated with sewage water (SW) caused a significant increase (p < 0.05) of Fe, Mn, Cu, Zn and Pb as compared to irrigated ground water (GW). Where was no significant effect in growth of the grass as shown for heavy metals concentrations as Cd, Ni, Co and Cr.
Abstract: Use of sewage water for irrigation improved chemical properties and fertility status in soil. Sewage water contains elements essential for plant growth and also contains heavy metals which may be toxic for animals if their concentration exceeds than permissible limit. To monitor this situation, a survey was conducted to ascertain the addition of he...
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Biosorption of an Industrial Dye (A-BG) by a Dairy Sludge
Mohamed Sassi,
Benaouda Bestani,
Eric Guibal
Issue:
Volume 3, Issue 5, October 2014
Pages:
292-298
Received:
4 November 2014
Accepted:
15 November 2014
Published:
18 November 2014
Abstract: Dairy sludge was investigated as potential adsorbent for the removal of hazardous cationic dyes. Biosorption was studied as a function of solution initial pH, biosorbent dose, biosorbent particle diameter and initial dye ion concentration. These parameters were measured in batch experiments. Equilibrium uptake increased with increasing dye concentration with a maximum sorption capacity of a 178.6 mg g-1. Model equations such as Langmuir and Freundlich isotherms were used to analyze the adsorption equilibrium data and the best fits to the experimental data were provided by the first isotherm model. Scanning electron microscopy and energy-dispersive X-ray (SEM-EDX), Brunauer–Emett–Teller (BET), Fourier transform infrared analyses (FTIR) and microbiological characterisation were also performed to characterize the biosorbent. To describe the adsorption mechanism, kinetic models such as pseudo-second-order and the intra particle diffusion were applied.
Abstract: Dairy sludge was investigated as potential adsorbent for the removal of hazardous cationic dyes. Biosorption was studied as a function of solution initial pH, biosorbent dose, biosorbent particle diameter and initial dye ion concentration. These parameters were measured in batch experiments. Equilibrium uptake increased with increasing dye concent...
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