Showing papers in "Environmental Progress in 2014"

Effect of hydrothermal carbonization reaction parameters on the properties of hydrochar and pellets

Abstract: Hydrothermal carbonization (HTC) is a promising upgrading process to convert various low energy-density lignocellulosic biomass materials to homogeneous, energy-dense HTC biochar, known as hydrochar. A novel two-chamber reactor was designed and built to investigate the effects of HTC reaction parameters on the resulting hydrochar produced from woody biomass. Reaction parameters investigated included temperature (200–230°C), feedstock particle size (0.60–2.38 mm), and reaction time (1–5 min). Mass yield and higher heating value (HHV) of the hydrochar products were determined as two important measures. Reaction temperature was found to have a much stronger influence on mass yield and HHV than particle size or reaction time. Hydrochar can be formed readily into robust, dense pellets, without requiring any additional binding agent. Pellet density ranged from 1260 to 1320 kg m−3, while volumetric energy density ranged from 27.3 to 29.5 GJ m−3. Several analyses were performed on hydrochar pellets, including ultimate analysis, proximate analysis, and water immersion tests. Results are presented and discussed to illustrate the chemical composition, energy density, and water resistance of hydrochar pellets. This study confirmed that the HTC process can transform lignocellulosic biomass into a solid fuel with favorable properties, and provides insightful guidance regarding optimum reaction parameters for producing hydrochar and pellets in a continuous, industrial process. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 676–680, 2014

Adsorption of basic dye onto raw and surface‐modified agricultural waste

Abstract: The application of raw Bangalora (Totapuri) mango seed kernel powder (RMS) and surface-modified Bangalora (Totapuri) mango seed kernel powder (SMMS) for the removal of methylene blue (MB) dye from aqueous solution was investigated under ambient conditions. The adsorbent was characterized by the FTIR and SEM analyses. Batch adsorption studies were conducted by varying the solution pH, adsorbent dose, initial MB dye concentration, and contact time. The optimum conditions for the adsorption of MB dye onto the adsorbent was found to be: pH (8.0), adsorbent dose (1.0 g: RMS and 0.4 g: SMMS), contact time (60 min: RMS and 30 min: SMMS), temperature of 30 � C for an initial MB dye concentration of 100 mg/L. Adsorption isotherm data were analyzed by the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models. Experimental data was successfully applied to the Freundlich model than the Langmuir model, and the maximum monolayer adsorption capacity was found to be greater for SMMS than the RMS. Adsorption kinetics was tested with the pseudo-first-order and pseudo-second-order kinetic models. The kinetic results show that the adsorption process followed the pseudo-second-order kinetic model. Adsorption kinetic data were further applied to the intraparticle diffusion, Boyd kinetic and shrinking core models to explain the adsorption mechanism. Adsorption mechanism results shows that the adsorption process was controlled by both internal and external diffusion. The results of this study show that the SMMS could be used as an effective and low-cost adsorbent for the removal of dyes from aqueous solution. V C 2013 American Institute of Chemical Engineers Environ Prog, 33: 87–98, 2014

Low cost adsorbents from agricultural waste for removal of dyes

Abstract: Low cost adsorbents from agricultural waste like rice husk was developed with various activation methods and tested for the removal of aqueous contaminants. Adsorption of a basic dye, malachite green (MG), from aqueous solution onto nitric acid treated (NRH), and peroxide treated rice husk (PRH) have been investigated. Various experiments were studied using batch adsorption technique under different conditions of pH, adsorbent dosage, initial dye concentration, and temperature. The adsorption capacities of MG by the NRH and PRH were essentially due to electrostatic forces. The NRH and PRH adsorbents had a relatively large adsorption capacity (18.1 and 26.6 mg/g). The adsorbent PRH had a higher surface charge at alkaline pH and enhanced removal of MG was obtained under alkaline conditions. Typical adsorption kinetics indicated the pseudo second-order kinetics behavior. The adsorption isotherms obeys Langmuir isotherm model. It was observed that the rate of adsorption improves with increasing temperature and the process is endothermic nature. The negative value of the change in Gibbs free energy (ΔG°) indicates that the adsorption of MG on PRH and NRH is feasible and spontaneous

Adsorption kinetics, mechanism, isotherm, and thermodynamic analysis of copper ions onto the surface modified agricultural waste

Abstract: The adsorption of copper ions onto the surface modified Strychnos potatorum seeds (SMSP) in a batch adsorption system has been studied. Kinetics, mechanism, isotherm, and thermodynamic parameters have been estimated. Adsorption kinetics of copper ions onto the SMSP follows a pseudo-second order kinetic model. Adsorption mechanism was explained with the intraparticle diffusion model, Boyd kinetic model (BKM), and Shrinking core model (SCM). Adsorption process was found to be controlled by both intraparticle diffusion and film diffusion. The diffusivity values were estimated from the BKM and SCM. Adsorption isotherm data agreed well with the Freundlich adsorption isotherm model, which indicates the multilayer adsorption of copper ions onto the SMSP. The maximum monolayer adsorption capacity of the SMSP was found to be 248 mg of copper ions/g of SMSP. Adsorption thermodynamic studies show that the adsorption of copper ions onto the SMSP was spontaneous and exothermic in nature. © 2012 American Institute of Chemical Engineers Environ Prog, 33: 28–37, 2014

Analyzing remediation potential of wastewater through wetland plants: A review

Abstract: Treatment of different wastewater using macrophytes-vegetated constructed wetland reveals its potential in terms of significant reduction in BOD, COD, suspended solids, total solids, total nitrogen, heavy metals along with remediation of xenobiotics, pesticides and polyaromatic hydrocarbons. The rhizosphere of macrophytes such as Phragmites, Typha, Juncus, Spartina and Scirpus serves as an active and dynamic zone for the microbial degradation of organic and sequestration of inorganic pollutant resulting in successful treatment of domestic, textile and other effluents. Up to 2049–6648 µg metal per gram dry weight of plant biomass are found to accumulate in plant parts i.e. shoots and roots. Major metal removal mechanisms are bioaccumulation in plant parts, phytoextraction and phytostabilization. Different wastewaters treated through this technology are industrial, domestic, dairy, pesticides, PAHs, and xenobiotics containing effluents. Loading limits of the wetland, removal efficiency, biomass disposal and variation in seasonal growth are some of the limiting factors which can be overcome by stimulating the plant microbe interaction through designer rhizospheres involving pigmentation, biostimulation and genetic alterations of plant and associated microbial community. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 9–27, 2014

Pyrolysis of mixtures of palm shell and polystyrene: An optional method to produce a high-grade of pyrolysis oil

Abstract: This research attempted to demonstrate a simple method to produce high-grade pyrolysis oil by maximizing the use of biomass wastes. In this study, the results of pyrolysis of palm shell alone are compared with pyrolysis of palm shell/polystyrene mixtures (1:1 weight ratios). Pyrolysis was carried out in a fixed-bed reactor under the following conditions: a temperature of 500°C, a nitrogen flow rate of 2 L/min, and reaction time of 60 min. The results showed that the final oil yield of palm shell pyrolysis was about 46.13 wt %. By mixing the palm shell with polystyrene, the yield of oil increased to about 61.63%. In these experiments, the high heating value was low (11.94 MJ/kg) for oil from pyrolysis of palm shell. By contrast, the high heating value was a high 38.01 MJ/kg for oil from pyrolysis of material mixtures. In addition, by using this method, more waste matter can be consumed as raw material for pyrolysis oil production, which also benefits waste management and energy security in Malaysia. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1026–1033, 2014

Removal of arsenic from drinking water by batch and continuous electrocoagulation processes using hybrid Al‐Fe plate electrodes

Abstract: Removals of arsenic from drinking water by electrocoagulation (EC) process using six different combinations of hybrid electrodes (Al-Fe), and Al-Al or Fe-Fe electrodes as all anodes and cathodes in a batch mode were evaluated. The removal process with monopolar series mode at optimum operating conditions (2.50 A/m2, 150 µg/L, and pH 7.0) indicated that Fe-Al-Al-Fe (anode-cathode-anode-cathode) hybrid plate electrode pairs were the most efficient choice in terms of arsenic removal efficiency (96% in 1 min) and operating cost (0.00202 €/m3). The arsenic removal from drinking water by continuous EC (CEC) process using Fe-Al-Al-Fe hybrid plate electrode pairs was also studied with respect to flow rates and initial arsenic concentrations. The effluent arsenic concentration of ≤10 µg/L in the CEC process was achieved at 3 min for 0.05 L/min (5.9 µg/L), 8 min for 0.10 L/min (6.3 µg/L), and 20 min for 0.20 L/min (8.4 µg/L), respectively. Amounts of the sludge and operating costs in the CEC process with respect to some experimental parameters such as operating time (3–20 min) and flow rate (0.05–0.20 L/min) at 150 µg/L were determined as 0.0095–0.025 kg/m3 and 0.009–0.060 €/m3. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 131–140, 2014

Adsorption of lead(II) ions from simulated wastewater using natural waste: A kinetic, thermodynamic and equilibrium study

Abstract: Locally available natural waste such as cashew nut shell (CNS), a byproduct of cashew nut industry, was found to be a low-cost material and also a promising adsorbent for removing lead(II) ions from simulated wastewater. A batch adsorption study was carried out with various adsorption parameters, such as solution pH, CNS dose, contact time, initial lead(II) ion concentration, and temperature. The kinetic data were analyzed using four adsorption kinetic models: the pseudo-first-order and pseudo-second-order equations, intraparticle diffusion, and Boyd kinetic equation to determine the best fit equation for the adsorption of lead(II) ions onto CNS. Kinetics of lead(II) ions adsorption by CNS is better described by the pseudo-second-order equation. Various thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, have also been evaluated and it has been found that the adsorption process was feasible, spontaneous, and exothermic in nature. The experimental data were analyzed using the Freundlich, Langmuir, and Dubinin–Radushkevich adsorption isotherm equations. The equilibrium data were found to fit well in the Freundlich isotherm, which confirmed the multilayer coverage of lead(II) ions onto CNS. The Langmuir monolayer adsorption capacity of the CNS was found to be 17.82 mg/g. A single-state batch adsorber system was designed to estimate the amount of adsorbent required to treat the known volume of the effluent using the Freundlich adsorption isotherm model. The results indicate that the CNS can be used to effectively adsorb lead(II) from wastewater. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 55–64, 2014

Two years experience of the BioDME project—A complete wood to wheel concept

Abstract: Dimethyl ether (DME), is an excellent diesel fuel that can be produced through gasification from multiple feedstocks. One particularly interesting renewable feedstock is the energy rich by-product from the pulping process called black liquor (BL). The concept of utilizing BL as gasifier feed, converting it via syngas to DME and then compensating the withdrawal of BL energy from the pulp mill by supplying biomass to a conventional combined heat and power plant, is estimated to be one of the most efficient conversion concepts of biomass to a renewable fuel on a well-to-wheel basis. This concept has been demonstrated by the four-year BioDME project, including field tests of DME-fueled heavy-duty trucks that are operated commercially. Up till the summer of 2013 more than 500 tons of BioDME has been produced and distributed to 10 HD trucks, which in total has run more than 1 million km in commercial service. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 744–750, 2014

Utilization of calcined Ni‐Al layered double hydroxide (LDH) as an Adsorbent for removal of methyl orange dye from aqueous solution

Abstract: In the present work, Ni-Al layered double hydroxide (Ni-Al LDH) was synthesized by coprecipitation method from their nitrate salts and utilized as an adsorbent for the removal of methyl orange (MO) dye from its aqueous solution. The synthesized Ni-Al LDH was characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), and N2 adsorption– desorption analysis. Batch adsorption isotherm experiments were conducted with methyl orange dye at three different temperatures (30, 40, and 50 � C). Adsorption isotherm data were fitted with Langmuir, Freundlich, and Redlich–Peterson models. It was found that the Langmuir and Redlich–Peterson isotherm models best described the adsorption of MO on calcined Ni-Al LDH. The experimental results revealed that the increase in temperature increases the adsorption capacity of MO on calcined Ni-Al LDH adsorbent. The maximum adsorption capacity was found to be 5.7 3 10 24 mol g 21 at 50 � C. The influence of pH on the adsorption of MO dye indicated that the adsorbent has good structural stability in the studied pH range. Thermodynamic studies authenticated that the adsorption of MO dye on calcined Ni-Al LDH was spontaneous, endothermic and entropy driven process. The results indicate that the calcined Ni-Al LDH can be employed as an adsorbent for removal of dye from aqueous solution. V C 2013 American Institute of Chemical Engineers Environ Prog, 33: 154–159, 2014

Techno-economic assessment of nonfossil ammonia production

Abstract: The production of nitrogen fertilizers are almost exclusively based on fossil feedstocks such as natural gas and coal. Nitrogen fertilizers are a necessity to maintain the high agricultural production that the world's population currently demands. Ammonia produced from nonfossil-based feedstocks would enable renewable production of ammonia. Renewable feedstocks are one thing, but perhaps even more important in the future are the security of supply that decentralized production enables. In this study, the techno-economic evaluation of production of ammonia from various renewable feedstocks and for several plant sizes was investigated. The feedstocks included in this study are grid-based electricity produced from wind power, biogas, and woody biomass. The feedstocks differed in exergy, and to make a fair comparison, the electric equivalence ratios method was used. The results showed that the energy consumption for biogas and electricity is the same at 42 GJ/tonne ammonia. When using the electric equivalence comparison for the same cases, the results are 26 and 42 GJ/tonne, respectively. Biomass-based production has an energy consumption of 58 GJ/tonne and 31 GJ/tonne when using the electric equivalence comparison, which should be compared with the industrial average of 37 GJ (or 21 GJ electric equivalence) per tonne of ammonia. Monte Carlo simulations were used to vary the inputs to the process to evaluate the production cost. The ammonia production cost ranged from $680 to 2300/tonne ammonia for the various cases studied (Less)

Determination of kinetic parameters of biomass samples using thermogravimetric analysis

Abstract: In this work, thermogravimetric analysis is carried out on four different biomass samples such as bagasse, coir–pith, groundnut shell and casuarina leaves to study their thermal behaviour. Analysis is put through in an inert nitrogen atmosphere from ambient temperature to 800°C at a heating rate of 10°C/min. Three reaction zones corresponding to dehydration, hemicellulose–cellulose degradation and lignin degradation are observed for all four biomass samples. The kinetic parameters such as activation energy, pre–exponential factor and order of the reaction for all the components of samples are determined using the simple Arrhenius equation. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 256–266, 2014

Degradation of Alizarin Yellow R using UV/H2O2 advanced oxidation process

Abstract: The homogeneous advanced oxidation process of ultraviolet (UV) radiation in presence of hydrogen peroxide (H2O2) was utilized to degrade Alizarin Yellow R, one of the most commonly used azo dyes in the textile industry. In this study, the effects of initial H2O2 concentration, initial dye concentration, initial pH, and temperature were examined to determine the optimum conditions for maximum degradation. Complete degradation was achieved within 1 h, for all the experimental conditions studied in the present work. The Box–Behnken response surface methodology (RSM) was used for optimizing the variables of the degradation process. Based on the estimated optimum conditions, 92.7% of degradation was achieved. The degradation process was found to follow first order kinetics. The estimated rate constants, along with the optimized conditions will be of useful for the design and scale up of the combined UV/H2O2 process for the said purpose. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 482–489, 2014

Analysis of product distribution and characteristics in hydrothermal liquefaction of barley straw in subcritical and supercritical water

Abstract: In this study, hydrothermal liquefaction of barley straw in subcritical and supercritical water with potassium carbonate catalyst was performed in the temperatures range of 280–400°C. The influence of final reaction temperature on products yield was investigated and some physicochemical properties of products were analyzed. It was found that products yield was significantly influenced by final reaction temperature under slow heating rate. The biocrude yield increased first and then declined as the temperature increased while the yield of solid residues showed the opposite trend. The highest biocrude yield (35.24 wt %) as well as the maximum energy recovery of 55.33% were obtained at 300°C. The products obtained were characterized in terms of CHNS elemental composition, higher heating values (HHVs), Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometer (GC-MS). Biocrude with more than 74% of C and H contents was produced under tested conditions with HHVs of 26.75–35.48 MJ/kg. The biocrude mainly consisted of carboxylic acids, phenolic compounds, and ketones, as well as some aldehydes and alcohols. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 737–743, 2014

Preparation and characterization of activated carbon from Kraft lignin via KOH activation

Abstract: Kraft lignin (KL), which is largely obtained from Kraft pulping process, is typically utilized to generate steam, electricity, and heat. The huge amount of KL can also be utilized for various purposes such as producing biofuels, chemicals, and materials. In this work, industrial waste KL was used to prepare activated carbons (ACs) with high surface area and large pore volume via KOH activation method. The effects of pretreatment methods of KL, activation methods, and activation conditions on the pore structures and the yield of ACs were investigated. The prepared ACs were characterized by XRD, SEM, FTIR, and N2 adsorption at −196°C. The results showed that the pore structure and the yield of ACs were closely related to the various pretreatment methods, activation methods, and conditions. A 26% carbon yield of AC with the maximum BET surface area of 2762.5 m2/g and pore volume of 1.32 cm3/g was obtained under the following activation condition (a) KOH to acid pretreatment KL mass ratio of 4, (b) activation temperature of 750°C, (c) activation duration of 2 h, and (d) N2 flow rate of 160 cm3/min. The activating agent KOH can be recovered partially and the washing water discharge can also be minimized by reuse process. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 519–526, 2014

Effect of biochar on carbon dioxide release, organic carbon accumulation, and aggregation of soil

Abstract: The potential carbon sequestration ability of biochar was investigated. The results indicated the amendment of biochar to soil could reduce the CO2 emission and increase the organic matter of soil effectively. The influence extent enhanced as the increase of biochar and the influence extent on soil with lower organic matter content is much obvious than soil with higher organic matter content. After incubated 7 months, soil CO2 emission was suppressed significantly by the amendment of biochar. The CO2 release amount in soils with 8% biochar decreased 29%∼39% compared with control. Organic matter content in soils with 8% biochar increased 41%∼75%. In addition, biochar promoted the formation of soil aggregates. Mean weight diameter of micro-aggregates in soils with biochar increased obviously compared with the control, indicating that stability of soil aggregates improved as the increase of biochar. The research demonstrated that biochar had potential ability on soil carbon sequestration, which was realized by enhance organic matter content, suppressing CO2 release and improving micro-structure characteristic of soil. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 941–946, 2014

Devolatilization behavior and pyrolysis kinetics of potential Tunisian biomass fuels

Abstract: Biomass thermochemical conversion is complex and requires a good understanding of the thermal decomposition process. This process may be identified using mass loss kinetics which are useful for the design of proper equipment used for biomass conversion. This work aims to determine devolatilization kinetic parameters characterizing four Tunisian biomass species: industrial by product (Pine Sawdust), agro-industrial by product (Olive Solid Waste), agricultural residue (Date Palm Trunk) and seaweed (Posidonia Oceanica) using data from non-isothermal thermogravimetry and the Coats and Redfern calculation method. Decomposition TG and DTG data were analyzed by applying 10 kinetic models including processes governed by nuclei growth, surface nucleation followed by geometric, diffusion and chemical reaction models. Obtained results show that biomass pyrolysis is represented by two successive steps: (i) devolatilization stage characterized by high weight loss rate, which is well described by diffusional, surface nucleation followed by geometric and first order chemical reaction models. (ii) char formation stage characterized by low weight loss rate, which is well described by second order and third order chemical reaction models. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 1452–1458, 2014

Direct production of gasoline and diesel fuels from biomass via integrated hydropyrolysis and hydroconversion process—A techno-economic analysis

Abstract: A techno-economic analysis (TEA) is performed to investigate the production of gasoline and diesel range hydrocarbon fuels by conversion of woody biomass via Gas Technology Institute (GTI)'s integrated hydropyrolysis plus hydroconversion (IH2) process. The processing capacity is 2000 dry metric tonnes (2205 dry US tons) of woody biomass per day. Major process areas include catalytic hydropyrolysis, catalytic hydroconversion, on-site hydrogen production, feedstock handling and storage, hydrocarbon absorber, sour water stripper, hydrogen sulfide scrubber, distillation tower, and all other operations support utilities. The TEA incorporates applicable commercial technologies, process modeling using Aspen HYSYS software, equipment cost estimation, and discounted cash flow analysis. The resulting minimum fuel selling price is $1.64 per gallon (or $1.68 per gallon of gasoline equivalent) in 2007 US dollars. The process yields 79 gallons of liquid fuels per dry US ton of woody biomass feedstock, for an annual fuel production rate of 61 million gallons at 96% on-stream time. The estimated total capital investment for an nth-plant is $264 million. A sensitivity analysis captures uncertainties in costs and plant performance. Results from this TEA can serve as the baseline for future comparison and as a basis for comparing this process to other biomass-to-liquid fuel pathways. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 609–617, 2014

Life cycle analysis of an alternative to the haber‐bosch process: Non‐renewable energy usage and global warming potential of liquid ammonia from cyanobacteria

Abstract: The production of ammonia via the Haber-Bosch process consumes large amounts of fossil fuels and releases large amounts of greenhouse gases. Ammonia has many important applications including fertilizer for crops and for microalgae-derived biofuel systems. Aquatic cyanobacteria fix nitrogen from the air and have been mass-cultured for many uses. This study analyzes, on a life cycle basis, a process to culture the cyanobacterium, Anabaena sp. ATCC 33047, in open ponds; harvest the biomass and exopolysaccharides and convert these to biogas; strip and convert the ammonia from the biogas residue to ammonium sulfate; dry the ammonium sulfate solution to ammonium sulfate crystals; transport the ammonium sulfate and convert it to liquid ammonia and concentrated sulfuric acid. When compared to the ammonia produced via the Haber-Bosch process, savings of about 1.0 × 105 MJ of non-renewable energy and 3100 kg CO2 equivalent of global warming potential per 1000 kg of liquid ammonia might be possible. The results are robust and are not sensitive to the model parameters. The proposed system, if implemented, might have a significant impact on many important global issues such as global warming, fossil fuel depletion, and food security. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 618–624, 2014

Assessment of devolatilization schemes in predicting product yields of biomass fast pyrolysis

Abstract: Three devolatilization schemes to simulate biomass fast pyrolysis were tested and validated in this study. Fast pyrolysis is an attractive process in converting lignocellulosic biomass to valued products. Accurate numerical models can help understand the conversion process and be used for reactor design and optimization. This study used a numerical model that considered the multiphase hydrodynamics and chemical reactions of biomass fast pyrolysis. The gas and solid phases were simulated by using a multifluid model that considered multiple species in each phase. Three devolatilization schemes for biomass fast pyrolysis were incorporated into the model to simulate the tempo-spatial evolutions of all phases and species. The predicted product yields were compared and validated using experimental data. It was found that the best predictions were given by a scheme that used three components to represent biomass and also considered organic liquid cracking into gas. Under the reactor conditions studied, all three devolatilization schemes predicted relatively fast decomposition of biomass and the reactor hydrodynamics was not significantly affected by the specifics of the devolatilization schemes. Overall, an accurate devolatilization scheme to simulate the chemical changes of biomass particles is essential to predicting the product yield of biomass fast pyrolysis at the reactor scale. © 2014 American Institute of Chemical Engineers Environ Prog,, 33: 756–761, 2014

Effects of foam agent on characteristics of thin-film transistor liquid crystal display waste glass-metakaolin-based cellular geopolymer

Abstract: Thin-film transistor liquid crystal display (TFT–LCD) waste glass comprises mainly SiO2 and Al2O3, which are suitable raw materials for geopolymer. This study investigates the effects of the amount of foam agents on the properties of waste glass-based cellular geopolymer. In this investigation, samples underwent a series of tests to determine their quality, including mechanical characterization, compressive strength, flexural strength, fire resistance, thermal conductivity, Fourier transform infrared spectroscopy, and scanning electron microscopy. The experimental results show that the mechanical strength and thermal conductivity decreased with the addition of foam agents, indicating that foam agents can reduce the thermal transfer. The pore volume increased with the amount of increase in foam agent. These results indicated that the amount of foam agent has a more substantial effect than waste glass replacement in geopolymers. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 538–550, 2014

Combination of advanced oxidation processes and biological treatment for the removal of benzidine‐derived dyes

Abstract: Dyes are widely used in the textiles industry in order to color their products. Textile industry consumes large volume of water and produce large amount of wastewater during all phases of textile production and finishing. The release of colored wastewater from these industries may present an ecotoxic hazard. Color removal and toxicity reduction, especially from textile effluents, have colossal challenge in recent decades, and up to now there is no single and cost-effectively attractive treatment that can effectively decolorize and the dye effluent treatment. The objective of this review article is to propose a textile wastewater treatment technique from the environmental friendly. An attempt is made to define and evaluate the Advanced Oxidation Processes (AOPs) as efficient techniques for the treatment of industrial dyes and many other pollutants in textile industry wastewater. However, in general AOPs are not cheap techniques. By means of oxidation process, most pollutants will be converted into molecules, which, in general are better biodegradable. The feasibility of combining different AOPs and biotechnology techniques is considered and evaluated according to their decontamination efficiency of benzidine-derived azo direct dyes used in the cotton textile industry. Ozonation in combination with aerobic biological treatment results as the more feasible system for color removal, total organic carbon, chemical oxygen demand, and toxicity reduction. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 873–885, 2014

Combination of an electrochemical pretreatment with a biological oxidation for the mineralization of nonbiodegradable organic dyes: Basic yellow 28 dye

Abstract: The aim of this article was to examine the feasibility of combining an electrochemical degradation of wastewater containing Basic Yellow 28 (BY28) dye on Pb/PbO2 electrode and a biological treatment. A central composite design (CCD) was used for the screening of the significant operating parameters and the identification of the most relevant interactions. The model equation obtained led to a classification of these parameters based on their level of significance, namely temperature followed by the initial concentration of BY28, the current density and the agitation speed. A significant interaction occurred between the temperature and the initial dye concentration. The second-order model obtained by CCD led to the following optimal conditions for dye degradation: 50 ≤ T ≤ 60°C, 8.125 ≤ i ≤ 25 mA cm−2, [BY28]0 = 134 mg L−1, and ω = 720 rpm. Under these conditions, the obtained BY28 dye degradation yield was 96%. The (BOD5/COD) ratio increased from 0.076 initially to 0.30 after pretreatment, showing that the electrochemical pretreatment of BY28 dye generate intermediate products, which are at least partially biodegradable. Microbial degradation was therefore performed for the pretreated solution in an aerobic batch reactor for 30 days using an activated sludge culture. A decrease of the residual amount of intermediate products contained in the electrolyzed solutions was observed which can be related to a biological oxidation, leading to 93% removal of the dissolved organic carbon by the combined process. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 160–169, 2014

Two Ecotypes of Hyperaccumulators and Accumulators Affect Cadmium Accumulation in Cherry Seedlings by Intercropping

Abstract: The appropriate hyperaccumulator intercropping can reduce heavy metals accumulation in crop. In the current study, two ecotypes (Mining ecotype and Farmland ecotype) of Conyza canadensis (L.) Cronq. (cadmium accumulator), Solanum nigrum L. (cadmium hyperaccumulator), and Digitaria sanguinalis (L.) Scop. (cadmium and plumbum accumulator) were collected from plumbum-zinc mine and non-heavy metal contaminated farmland, respectively. They affected cadmium accumulation in cherry seedlings by intercropping. The cadmium accumulation in cherry seedlings was reduced by hyperaccumulators and accumulators. The contents of cadmium in cherry shoots were: monoculture > intercropping with D. sanguinalis (farmland) > intercropping with D. sanguinalis (mining) > intercropping with C. canadensis (farmland) > intercropping with C. canadensis (mining) > intercropping with S. nigrum (farmland) > intercropping with S. nigrum (mining). Moreover, intercropping with mining ecotype of hyperaccumulators or accumulators, the cadmium accumulation in cherry shoots was less than that intercropping with farmland ecotype. Therefore, all of hyperaccumulators and accumulators in this study could be used for remedying the cadmium contaminated cherry orchard, with mining ecotype of S. nigrum as the best material. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 1251–1257, 2014

Adsorption studies of methylene blue onto activated saw dust: kinetics, equilibrium, and thermodynamic studies

Abstract: This study is devoted to the application of activated saw dust (ACSD) as adsorbent for the removal of “methylene blue (MB)” from the aqueous solutions. Raw saw dust was activated by a simple and low cost chemical method. After activation, adsorbent was characterized by scanning electron microscopy for its surface characteristics. Brunauer-EmmettTeller surface area and average particle size were determined and found to be 74.23 m/g and 700 mm, respectively. Removal efficiency of adsorbent for MB was demonstrated by batch adsorption experiments. pH study indicates that 9.5 pH is optimum for higher removal of MB. Temperature studies revealed exothermic nature of adsorption process. On studying kinetic models, it was observed that removal process is governed by pseudo-first-order kinetics. Intraparticle diffusion study revealed that it is not rate limiting step in removal process. Mass transfer coefficient was also determined. Value of DG was found to be negative at all studied temperature which confirms the feasibility of process. Langmuir’s adsorption isotherm was found to be suitable for this system. This study revealed that ACSD can be used as alternates of costly adsorbents for the removal of MB from effluents. VC 2013 American Institute of Chemical Engineers Environ Prog, 33: 790–799, 2014

Raw material selection for pulping and papermaking using TOPSIS multiple criteria decision making design

Abstract: General approach for determining the suitability of a feedstock for pulping and papermaking includes chemical-morphological analysis, cooking experiments, pulp characterization, and physico-chemical properties evaluation. This work attempts to simplify this raw material selection problem using a multi-criteria decision making (MCDM) approach exclusively on the basis of chemical–morphological analysis. Technique for order preference by similarity to ideal solution (TOPSIS) has been applied to the decision making unit comprising chemical and morphological characteristics of three Eucalyptus and Leucaena varieties to evaluate and rank them according to preference for pulping and papermaking. The applicability of the proposed methodology has been illustrated through three examples collected from literature. Results obtained in this investigation are in confirmation of the results published in literature. It reveals that the proposed method is practical, feasible, and easy to apply for pulp and paper based raw material selection. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1034–1041, 2014

Thermodynamic Analysis of Hydrogen Production from Model Compounds of Bio-oil Through Steam Reforming

Abstract: With the minimization of the Gibb’s free energy, the thermodynamical analysis of the steam reforming processes for the four typical model compounds (ethanol, acetic acid, acetone, and phenol) of bio-oil was systematically performed. In the steam reforming process, the four model compounds can be completely converted. The higher hydrogen yields of the four compounds were obtained via steam reforming than via thermal decomposition. The hydrogen yields first increased and then remained constant and even decreased with temperature, monotonically decreased with the pressure increase, and obviously increased with the steam to carbon ratio. As the steam to carbon ratio rose, the temperatures of the maximum hydrogen yields move afterward to low temperature. When the S/C ratio was 6, the increase rate of hydrogen was decreased. In the co-existence of CaO/CO2/H2O, the reaction between CaO and CO2 was dominant to the reaction between CaO and H2O. By adding CaO, a CO2 sorbent in the steam reforming system, both the yields and the concentration of hydrogen were obviously more pronounced than the processes without CaO. V C 2013 American Institute of Chemical Engineers Environ Prog, 33: 1008–1016, 2014

Treatment of antibiotic fermentation‐based pharmaceutical wastewater using anaerobic and aerobic moving bed biofilm reactors combined with ozone/hydrogen peroxide process

Abstract: Zi-Peng Xing, De-Zhi Sun, Xiu-Juan Yu, Jin-Long Zou, and Wei Zhou Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People’s Republic of China, Department of Environmental Science, Heilongjiang University, Harbin 150080 People’s Republic of China; xzplab@163.com (for correspondence) Key Laboratory of Chemical Engineering Process & Technology for High-efficiency Conversion, Department of Environmental Science, Heilongjiang University, Harbin 150080, People’s Republic of China College of Environmental Science and Engineering, Department of Environmental Science, Beijing Forestry University, Beijing, 100083 People’s Republic of China