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The objective of this study was to prepare an adsorbent material from eggshells of chicken banished to the ambient as wastes to satisfy the ecological requirements of sustainable. The preparation process based on the extraction of calcium ions from eggshells and these ions must be reacted with iron to form nanoparticles of (Ca/Fe)-layered double hydroxides (LDHs) which immobilized as Na-alginate beads. Molar ration of calcium to iron, pH and dosage of LDH nanoparticles must be equal to 1, 12 and 5 g/100 mL to ensure that the prepared beads have highest ability to remove of Amoxicillin (AMOX) antibiotic with removal efficiency equal to 32% for operational conditions of Co=100 mg/L, beads dosage=0.5 g/50 mL, speed=200 rpm, pH=7 for 3 hrs. To increase this efficiency to ≥ 90%, best conditions must be time 90 min, pH 7, and beads mass 1.2 g/ 50 mL for Co 100 mg/L at 200 rpm in the batch mode. The Pseudo second order has high capability in the description of such tests with coefficient of determination (R2 ) ≥ 0.9924 and sum of squared error (SSE) ≤ 0.1287. Hence, the sorption of AMOX onto beads is governed by the chemisorption process. The reflections of XRD analysis proved the presence of (Ca/Fe)-LDH nanoparticles with size of 13.49 nm, calcium hydroxide (Ca(OH)2) and calcium carbonate (CaCO3) [ABSTRACT FROM AUTHOR]

Groundwater is a valuable resource whose purity is necessary for human survival. It serves as a significant source of water for household, industrial, and agricultural purposes. Traditional groundwater pollution remediation technologies include pump & treat, phase extraction, aeration gas of groundwater, bioremediation, and chemical oxidation. Permeable reactive barrier (PRB) is one of the most key technology being developed as alternatives to the pump and manage method for the remedying contaminated groundwater. An overview on the groundwater significant as important sources for water, sources of groundwater contamination, transport of contaminants, and groundwater remediation technologies have been discussed in this paper. In addition to reactive media, the design and installation of PRBs of funnel-gate configurations and their application as a remediation technique have been covered in this review. Finally reaction mechanisms in groundwater, contaminant transport governing equation, isotherms sorption models, kinetic sorption models, breakthrough curves modeling have been presented in this review. PRB technique provides financial benefits while also encouraging waste material reuse, so contributing to environmental sustainability. Funnel and gate PRB can offer one or more dense treatment areas for maximizing groundwater pollution plume capture. Funnel-gate PRB is characterized by smaller reaction area, ease in replacement and removal during the blocking of the reactive barrier by fine soil particles and reactive sediments. [ABSTRACT FROM AUTHOR]

A novel adsorbent is synthesized from chicken bone wastes to support attempts to reuse them. To prepare the nanoparticles of calcium-iron oxide, the calcium ions have been extracted from chicken bones and combined with iron ions under specific conditions. Sodium alginate is used to immobilize the nanoparticles through synthesizing calcium/iron oxide - sodium alginate beads employed for tetracycline (TC) antibiotic adsorption. Batch experiments are conducted at a contact time of 0-180 min, initial TC concentration of 100-250 mg/L, agitation speed of 50-250 rpm, initial pH of 3-12, and beads dosage of 0.1-1.3 g/50 mL. The best vales for batch parameters are 90 min, 100 mg/L, 200 rpm, 7, and 1.3 g/50 mL, respectively. These conditions enable the beads to remove 97.116% of TC with 8 mg/g as maximum capacity. The precise formulation of the kinetic observations by the pseudo-second-order model indicates that the TC could be eliminated by chemical forces. The characterization tests provide evidence that nanoparticles formed inside the beads can support the sorption of TC, especially the particles that mainly consist of calcium-iron oxide. The beads are capable of removing TC from real groundwater with an efficiency smaller than that in the aqueous solution due to the presence of various chemicals. [ABSTRACT FROM AUTHOR]

This study presents a novel composite sorbent, synthesized from industrially inexpensive and abundant materials, designed for the remediation of groundwater contaminated by lead (Pb) and cadmium (Cd) ions through a permeable reactive barrier (PRB) technique. The synthesis process innovatively employs alum, a low-cost compound, alongside plaster kiln dust — a by-product waste from the gypsum industry — and Cetyl trim ethyl ammonium bromide (CTAB), to produce Nano-sized layered double hydroxide (LDH) composed of aluminum (Al+3) and calcium (Ca+2) ions. The synthesized LDH gel-solution was characterized using X-ray diffraction (XRD) analysis and subsequently intercalated onto an iron-slag surface, yielding a novel sorbent termed "iron-slag coated with (Ca/Al-CTAB)-LDH". The intercalation of CTAB and the presence of LDH nanoparticles significantly increased the iron-slag surface area from 0.48802 to 10.21 m² /g, thereby enhancing the adsorption capacity of the sorbent for Pb and Cd ions. Optimal synthesis parameters were identified as 0.035 g/50 mL CTAB, pH 10, (Ca/Al) molar ratio of 2, and an iron-slag dosage of 1 g/50 mL. Long-term column tests, spanning a duration of at least 25 days, were conducted, revealing a marked increase in the sorbent's longevity in the packed column when a low flow rate and inlet concentration of contaminants were combined with a high mass of sorbent. The experimental data from the breakthrough curves were successfully fitted by several models, including Bohart-Adams, Thomas-BDST, Yan, Belter-Cussler-Hu, and Clark expressions, with a determination coefficient (R2) exceeding 0.99 and a sum of squared errors (SSE) less than 0.162. The hydraulic conductivity of the packed sorbent remained largely constant at 2.7×10-2 cm/s, suggesting its suitability for PRB applications. The prepared sorbent demonstrated high efficacy in the removal of Pb and Cd ions from contaminated water, making it a promising tool for environmental remediation. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work uses a new nanoadsorbent after chemically synthesis from chicken eggshell wastes for removing amoxicillin (AMX) from aqueous solution. This removal was examined as a time function, initial concentration of AMX, pH, agitation speed, and adsorbent dosage. The study achieved the optimum time for equilibration in (90) min, at pH = 7 with an adsorbent dosage of 1.2 g. We applied many kinetic models to the sorption kinetic data where the pseudo-second-order model ( R 2 = 0.9924) was used to interpret the gained data at a rate constant K2 of (0.0077) g/(mg. min) at 200 rpm. Moreover, the adsorption calculated amount reached the experimentally required value and isotherm data best fitted the Langmuir model with R 2 (≥0.9486) than the Freundlich model. The intraparticle diffusion model revealed a diffusion dependent process. The different functional sets on the calcium/iron-surface as a layered double hydroxide (Ca/Fe)-LDH were important in sorpting the selected antibiotic. Forming (Ca/Fe)-LDH nanoparticles in the manufactured beads interacted with polluted water confirming that the nanoparticles own the prospective for acting as a latent sorbent to remove contaminants from aquatic media. [ABSTRACT FROM AUTHOR]

The utilization of vertical constructed wetlands (CWs) as a means of reusing textile wastewater for non-potable purposes is a unique step in the dissemination of this environmentally friendly method. The performance of unplanted and planted CW units was examined in relation to dye concentration (10-750 mg/L), hydraulic retention time (1-3 d), and substrate type (either filter-sand or waste foundry sand). With time, the used plants (Phragmites australis and Canna indica) have grown significantly in height and density. The results of the experiments showed that the pH of the effluents from these units was within the range of 6.5-8.5 that is considered acceptable by environmental regulations. The COD was removed from these effluents after 3 d, with removal efficiencies ranging from 46.8% to 80.5%. With a decrease in dye concentration and an increase in contact time, COD removal rates may be increased; Additionally, NH4-N and NO3-N removals did not exceed 65.5%. All units can remove color with an efficiency of 98% at the chosen dye concentrations. Findings demonstrated that WFS-packed units have efficacy values comparable to or higher than those of FS-packed units; as a result, WFS by-product can be utilized in CWs in place of FS. [ABSTRACT FROM AUTHOR]

The novel aspect of this research is the fabrication, characterisation, and application of an engineered adsorbent made from quartz sand coated with calcium ferric oxides (QS/CFO) derived from the wastepaper sludge ash (WPSA) for the removal of tetracycline (TC) from synthetic water. Initially, the new adsorbent was fabricated using a Ca/Fe molar ratio, sand/FeCl3 ratio, pH (of synthesising environment), ethylene glycol dose, and temperature of 1:0.75, 1:1, 12, 6 mL/100 mL, and 95 °C, respectively. Then, the new adsorbent was applied to treat water having 50 mg/L of TC in batch experiments, taking into account the effects of the contact time (0–180 min), pH of water (2–12), the dose of adsorbent (0.05–0.5 g), and agitation speed (0–250 rpm). The results obtained proved the engineered adsorbent can remove as much as 90% of the TC (adsorption capacity of 21.96 mg/g) within 180 min at an initial pH, adsorbent dosage, and agitation speed of 7, 0.3 g per 50 mL, and 200 rpm, respectively. It was also found that the pseudo-second-order model describes the kinetic measurements better than the pseudo-first-order model, which indicates that the TC molecules have been bonded with the prepared sorbent through chemical forces. Furthermore, the intra-particle diffusion model results demonstrated that the diffusion mechanism plays a significant role in TC adsorption; however, it was not the predominant one. Finally, the outcomes of the characterisation analysis proved that the newly formed layer on the quartz sand substantially contributed to the removal of the TC from the contaminated water. [ABSTRACT FROM AUTHOR]

This study investigates the efficacy of sand coated with calcium / aluminum (Ca/Al)-layered double hydroxide (LDH) in the elimination of methyl orange dye from simulated groundwater using method of permeable reactive barrier. For green (sustainable) manufacturing of this sand, aluminum prepared from dissolution of alum (cheap coagulant) can be interacted chemically with calcium extracted from cement kiln dust byproduct to create nanoparticles of Ca and Al that precipitate on the filter sand. Sorption measurements for interaction of methyl orange dye and coated sand was well formulated by Langmuir model with highest value of correlation (determination coefficient= 0.999) and lowest errors (sum of squared errors= 0.0122). Also, the maximum capacity of adsorption was valued of 0.9453 mg/g and the sorption curve can classify as “favorable” type. According to desorption measurements, little percentage of dye (0.91%) can desorb from exhausted coated sand through washing with water due to strength of bonding between sorbent and dye molecules. Also, the exhausted sorbent can regenerate with efficiency not less than 85% after eight of regeneration cycles. Finally, measurements of breakthrough curves in the continuous mode operation using column setup proved that the propagation of dye front (and consequently the longevity of barrier) would increase significantly with thicker barrier and lowest values of influent concentration and flow rate. COMSOL (computer solution) package can use effectively in the simulation of these curves. [ABSTRACT FROM AUTHOR]

The present work is represented by the derivation of mathematical model and solving the model analytically using the method of separation of variables to describe the migration of the contaminant metal ions through a column packed with bed of permeable reactive barrier (PRB). The validity of the solution can be evaluated through the simulation of cadmium and chromium ions using scrap iron and/or aluminum by-products in the form of wastes that if not utilized to treat waste by waste can impose further burden over the ecosystem. Breakthrough curves proved that the increase of metal ions velocity will decrease the capturing of the ions; therefore, the distribution coefficient and the retardation factor also decrease. Furthermore, the increase of barrier depth will increase the longevity of PRB because this will delay the migration of contaminant. A mathematical model has acceptable ability in the representation of experimental measurements with Nash-Sutcliff efficiency coefficients greater than 0.98. The longevity of the PRB was estimated for the field scale to be 210 and 250 d to produce contaminant effluent beyond 100 cm barrier matrix within the environmental permissible concentrations. Although groundwater velocity is highly variable, a proposed velocity of 0.25 cm/min which is assumed to be analogous to the groundwater velocity has revealed prolonged longevity of 7.02 y for the capture of chromium. [ABSTRACT FROM AUTHOR]

The effects of the washing process, purging solution, and buoyance force (inclined topography action) on the effectivity of the electro-kinetic method used to remediate of a silty clay loam and natural soils contaminated with Zn, Pb and/or Ni were investigated by applying 12 different experiments. The results revealed that the washing process and buoyance force can cause a small increase in the Zn removal efficiency (≤ 31%) when compared with non-washing approach using distilled water purging solution. Using 0.1 M of EDTA solution for the soil contaminated with listed metals in combination with washing can lead to significant increase in the removal efficiencies with percentages not greater than 58.4, 60.68 or 42.8%, respectively. In the presence of EDTA, however, the majority of metals passed through the soil media to the anode area. In contrast, these metals are accumulated near the cathodic region in the presence of distilled water. The results demonstrated that the buoyance force (resulted from inclination angle of 30°) with EDTA had adverse influence on the metal profile along the treated soil. Finally, the results certified that EDTA in electro-kinetic process coupled with soil washing is a new hybrid technique which achieved Pb removal efficiency from natural soil reached to 58% by improving the solubilization and transport of metal ions. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The focal point of this study was to use the waste foundry sand (WFS) in the remediation of simulated aqueous solution contaminated with ammonia nitrogen through batch and column tests. Recycling this waste is a real application for sustainable principles because it will reduce disposal costs and the required area in the sanitary landfill. Based on the kinetic sorption measurements for ammonia nitrogen onto WFS, the predominant mechanism was the chemisorption because the measurements were well fitted with the pseudo-second-order model. In comparison with the Freundlich model, the sorption isotherm data were well formulated by models of Langmuir and Sips with a maximum adsorption capacity of 1.152 mg/g. The breakthrough curves for a duration of 80 h certified that the two weight ratios (10:90 and 20:80) of WFS:sand were suitable for maintaining the reactivity and conductivity of permeable reactive barrier (PRB) for pollutant under consideration. The results proved that the increasing of WFS and bed depth increased the breakthrough and saturation times with the sorption capacity of the barrier. Also, the appearance of these curves was directly proportional to the inlet concentration of pollutants and the flow rate of contaminated water. Statistical measures specifically Nash–Sutcliffe efficiency and coefficient of determination were proved that the breakthrough curves were well described by Thomas, Belter, and Yan models. [ABSTRACT FROM AUTHOR]

Recycling of textile wastewater for non-potable purposes by sustainable constructed wetlands (CWs) has gained a great attention. In this work, unplanted and planted vertical subsurface flow CWs have been applied to remediate simulated wastewater contaminated with Congo red dye. This treatment implemented in four containers packed with sewage sludge bed under the variation of hydraulic retention time (HRT, 1-5 d) and inlet dye concentration (10-40 mg/L). Measurements stated that the heights and densities of Phragmites australis as well as Typha domingensis were increased from 0.15 m and 5 plant/unit at the beginning of plantation to values =1.65 m and 59 plant/unit, respectively, after 136 d. Results proved that the pH of the treated water ranged from 6.5 to 8.5, which is considered acceptable from an environmental view point. Also, an increase in the retention time with decrease of inlet dye concentration can accompany with a significant increment in the removal efficiencies of dye concentration and, consequently, the chemical oxygen demand (COD). Approximately 96.5% and 46% of dye concentration and COD, respectively, have been removed at the end of treatment period (=5 d) when the inlet concentration is 10 mg/L. The measurements of the effluent dye concentrations as a function of the retention times were well simulated by Grau second-order kinetic model. Based on the FT-IR analysis for sewage sludge beyond the treatment process, the removal of the Congo red dye from aqueous solution was enhanced by different functional groups such as phenols, carboxyl, aldehydes, lactones, ketones, quinones and anhydrides. [ABSTRACT FROM AUTHOR]

This work explores the suitability of iron slag solid waste as a sorbent in the permeable reactive barrier technology in order to achieve sustainability principles for remediating groundwater contaminated with benzaldehyde. Numerical modeling was able to simulate the measured breakthrough curves under various values of flowrates and initial concentrations with a coefficient of determination greater than 0.98. This model is based on solving of advection-dispersion-sorption equation using computer solution (COMSOL) Multiphysics 3.5a. Results certified that there was a direct relation between longevity of the barrier measured by breakthrough time and bed depth; however, this longevity was decreased dramatically with an increase of inlet concentration of contaminant and flowrate of flow. Hydraulic conductivity was recognized to remain approximately constant which certified that there was no precipitation occurred through the removal process. Finally, the dissolved calcium oxide (formed 14% of iron slag) enhanced the sorption process because calcium can compose the cation bridge between benzaldehyde and iron. [ABSTRACT FROM AUTHOR]

The present study modifies the sorption isotherm for simulating the influences of initial pH and temperature variations on the cadmium sorption from contaminated water using waste foundry sand based on Langmuir, Freundlich, and Temkin models. Results proved that the Langmuir expression is able to adopt these effects by relating sorption capacity and affinity constants with pH and temperature of aqueous solution through exponential relationships (determination coefficient = 0.9375). The present model is assumed that the sorption process occurs through acidic functional groups and this is consistent with FTIR outputs. Interaction of cadmium/WFS is found to be exothermic by thermodynamic analysis. [ABSTRACT FROM AUTHOR]

This work aims to investigate the ability of using waste foundry sand (WFS) resulting as inexpensive by-product from steel industry in the low permeability barrier (LPB) and permeable reactive barrier (PRB) technologies for restriction of the movement of lead and nickel ions in the groundwater. Outputs of flask and tank tests certified that this material could capture these ions with sorption efficiency greater than 95% at time, pH, sorbent dosage, and speed equal to 60 min, 4 for lead and 6 for nickel, 2.5 g/100 mL, and 250 rpm, respectively. Sorption isotherm measurements were represented in a good manner by Langmuir model in comparison with Freundlich model with coefficient of determination (R2) greater than 0.99. So, the chemisorption was the predominant mechanism which could be supported by O-H, H-O-H, C-O, O-Si-O, and Si-O functional groups based on the Fourier transform infrared analysis. The maximum sorption capacity of WFS was 13.966 and 4.227 mg/g for lead and nickel ions, respectively, with corresponding affinities equal to 0.647 and 0.099 L/mg. Measurements signified that the hydraulic conductivity of WFS was 3.8 × 10−7 cm/s which satisfies the requirements of LPB. To obtain the acceptable values of permeability and reactivity, PRB was prepared from mixing 18% WFS with 82% filter sand. COMSOL software was able to simulate the measurements of two-dimensional tank packed with Iraqi soil aquifer in combination with WFS-LPB and WFS-filter sand PRB. Thicker barriers have a high ability in the protection of locations in the down-gradient side because their longevity increased dramatically with increase of barrier thickness. [ABSTRACT FROM AUTHOR]

Reaction term in the transport equation which described the migration of metal ions in the porous medium is frequently represented by conventional kinetic models such as pseudo-first order, pseudo-second order, and others. Unfortunately, these models are applicable for the constant value of solution pH, and they cannot simulate the real situation in the field scale where this pH may be changed with time. Accordingly, the present study is a good attempt to derive the kinetic model that can simulate the change in the pH of the solution through solute transport. This was achieved by modifying the adsorption capacity and reaction constant to be functions in terms of solution pH by using semianalytical analysis and numerical approximation. The results proved that the kinetic model based on the numerical approximation (using exponential functions for adsorption capacity and reaction constant) symbolled as model 2 was more representative from other models applied for the description of interaction of nickel ions (with initial concentration of 400 mg/L) and cement kiln dust with sum of squared error ≤1.54913 and determination coefficient ≥0.889. Also, the developed models had high ability for recognizing between pure precipitation and pure adsorption. [ABSTRACT FROM AUTHOR]

Conversion of inert sand to the reactive material by plantation new active sites represented by iron oxide nanoparticles on its surface through simple impregnation can be considered the focal point of the present study. The conditions required to achieve the best impregnation were sand/ferric nitrate ratio of 2.5:1 g/g with initial pH of 11 which they specified based on the maximum values of cadmium sorption capacity (=0.8007 mg/g) and iron content (=1.1459 mg/g). The prepared coated sand by iron oxide (CSIO) has a good ability in the remediation of aqueous solution contaminated with copper and cadmium ions with removal efficiency exceeded the 92% under the best conditions of contact time, CSIO dosage, and initial pH equal to 1 h, 1 g/50 mL and 7 respectively. Pseudo-second-order and Langmuir models have described in a good manner the kinetic and isotherm sorption measurements with a coefficient of determination (≥0.9804) and the sum of squared errors (≤0.5496). Characterization tests for CSIO such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction proved that the iron oxide/hydroxide nanoparticles precipitated on the surface of sand particles and within the accessible pores. Fourier transform infrared spectroscopy analysis in combination with values of final pH revealed that the sorption mechanism was co-precipitation due to increase pH and complexation with surface of CSIO. Continuous tests proved that the longevity of the barrier in terms of breakthrough time was increased with a thicker bed in the permeable barrier technology and this barrier can be saturated with a contaminant as a function of the time. Also, results proved that the computer solution (COMSOL) Multiphysics has a good ability in the description of the transport of the contaminant in comparison with experimental measurements. [ABSTRACT FROM AUTHOR]

For the application of sustainability concepts, this study investigates the possibility of using iron slag by-product as reactive material in the permeable reactive barrier technology. This investigation was achieved based on the set of batch equilibrium and kinetic tests in combination with the prediction of the barrier – retardation factor as the main indicator for the longevity of this barrier. Results reveal that the removal efficiency was greater than 90% at best operational conditions specified by changing the pH, contact time, sorbent dosage, and agitation speed in the ranges of 3–7, 0–180 min, 0.5–12 g/100 mL, 0–250 rpm respectively for lead ions initial concentration of 50 mg/L. The maximum adsorption capacity of iron slag can be calculated by the Langmuir model because it is more representative of sorption data. This capacity (=2.309 mg/g) is compatible with the value calculated from pseudo-second-order which describes the kinetic data in a good manner, so, the ion exchange or chemisorption can be the predominant mechanism for sorption of lead ions. The X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy tests for reactive material supported this result where the dissolution of calcium oxide by hydrolysis and ion exchange can enhance the removal of lead ions by iron oxide surface sites. [ABSTRACT FROM AUTHOR]

The present study investigates the utilization of the waterworks sludge by-product that generated from water supply treatment plant for the remediation of simulated groundwater contaminated with leachate spilled from the sanitary landfill by permeable reactive barrier (PRB) technology. Batch sorption experiments were conducted for describing the interaction between the acetogenic phase (pH = 5.5 ± 0.1) of leachate contaminated with cadmium (Cd(II)), ammonia nitrogen (NH3–N) or dissolved organic matter (COD) and waterworks sludge. Also, conventional sorbents such as the activated carbon and amberlite ion-exchange resin were tested to evaluate their ability in comparison with waterworks sludge in the remediation process. Results proved that the Langmuir model describes well the sorption data with maximum sorption capacities of 5.634, 14.908 and 3.938 mg/g for Cd(II) onto sludge, NH3–N onto resin and COD onto activated carbon, respectively. The batch and column tests signified that the sludge, resin, and carbon can be used for removing Cd(II), NH3–N, and COD, respectively. The multi-layered bed of sorbents under consideration has a remarkable ability in the remediation of a leachate contaminated with Cd(II), NH3–N, and COD. Finally, the Yan model is more representative than Thomas and Belter models for characterization of the contaminants propagation in the column packed with single sorbent. [ABSTRACT FROM AUTHOR]

Copyright of Association of Arab Universities Journal of Engineering Sciences (JAARU) is the property of Association of Arab Universities and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Computer solutions (COMSOL) Multiphysics 3.5a software was used for simulating the one-dimensional equilibrium transport of the lead–phenol binary system including the sorption process through saturated sandy soil as the aquifer and granular dead anaerobic sludge (GDAS) as the permeable reactive barrier. Fourier-transform infrared spectroscopy analysis proved that the carboxylic and alcohol groups are responsible for the bio-sorption of lead onto GDAS, while phosphines, aromatic and alkane are the functional groups responsible for the bio-sorption of phenol. Batch tests have been performed to characterize the equilibrium sorption properties of the GDAS and sandy soil in lead and/or phenol containing aqueous solutions. Numerical and experimental results proved that the barrier plays a potential role in the restriction of the contaminant plume migration and there is a linear relationship between longevity and thickness of the barrier. A good agreement between these results was recognized with root mean squared error not exceeding 0.04. [ABSTRACT FROM AUTHOR]

We investigated the efficiency of granular dead anaerobic sludge (GDAS) biosorbent as a permeable reactive barrier for remediation of groundwater contaminated with lead–phenol (Pb-Ph) present simultaneously. Batch tests were performed to characterize the equilibrium sorption properties of the GDAS and sandy soil in the Pb-Ph containing aqueous solutions. Computer solutions (COMSOL) Multiphysics 3.5a software was used for simulating the two-dimensional equilibrium transport of lead–phenol including the sorption process through the saturated sandy soil in the presence of GDAS. A good agreement between the predicted and experimental results was recognized with the root-mean-squared error not exceeding 0.049. [ABSTRACT FROM AUTHOR]

An experimental study constituting eight different tests was performed to investigate the effect of relevant factors on the remedial efficiency of electro-kinetic process applied to clean-up Cu contaminant from three types of Iraqi soil. An efficiency enhancement scheme was employed involving pH control, acid-injection wells, and optimized potential gradient as part of the investigative program. With pH controlled within the range 2.5-3, four acid-injection wells, and a potential gradient of 0.8 V/cm; overall clean-up efficiencies of 85%, 58%, and 34% were achieved for sandy, sandy loam, and silty loam soils, respectively. [ABSTRACT FROM AUTHOR]

This study concerns the control of movement of light nonaqueous phase liquid (LNAPL) in unsaturated zone in the presence of relatively low permeability clay lens. A two-dimensional, finite-difference numerical model for the simultaneous movement of LNAPL and water through the unsaturated zone of the soil has been developed. The system is a three fluid phase system (water, LNAPL, and air) but in the derivation of the model, air was treated as an immobile phase at constant atmospheric pressure. The flow equations for LNAPL and water were cast in terms of the wetting and non-wetting fluid pressure heads, respectively. The finite-difference equations were solved implicitly with explicitly scheme using Newton-Raphson iteration with Taylor series expansion to treat nonlinearity. A physical model to represent the infiltration of kerosene above the clay lens was constructed. The numerical results were compared with those observed experimentally. The results of all tests showed that the presence of clay lens controls the vertical movement of LNAPL in heterogeneous porous medium. [ABSTRACT FROM AUTHOR]

The provision of safe water for people is a human right; historically, a major number of people depend on groundwater as a source of water for their needs, such as agricultural, industrial or human activities. Water resources have recently been affected by organic and/or inorganic contaminants as a result of population growth and increased anthropogenic activity, soil leaching and pollution. Water resource remediation has become a serious environmental concern, since it has a direct impact on many aspects of people's lives. For decades, the pump-and-treat method has been considered the predominant treatment process for the remediation of contaminated groundwater with organic and inorganic contaminants. On the other side, this technique missed sustainability and the new concept of using renewable energy. Permeable reactive barriers (PRBs) have been implemented as an alternative to conventional pump-and-treat systems for remediating polluted groundwater because of their effectiveness and ease of implementation. In this paper, a review of the importance of groundwater, contamination and biological, physical as well as chemical remediation techniques have been discussed. In this review, the principles of the permeable reactive barrier's use as a remediation technique have been introduced along with commonly used reactive materials and the recent applications of the permeable reactive barrier in the remediation of different contaminants, such as heavy metals, chlorinated solvents and pesticides. This paper also discusses the characteristics of reactive media and contaminants' uptake mechanisms. Finally, remediation isotherms, the breakthrough curves and kinetic sorption models are also being presented. It has been found that groundwater could be contaminated by different pollutants and must be remediated to fit human, agricultural and industrial needs. The PRB technique is an efficient treatment process that is an inexpensive alternative for the pump-and-treat procedure and represents a promising technique to treat groundwater pollution. [ABSTRACT FROM AUTHOR]

The possibility of using granular dead anaerobic sludge (GDAS) biosorbent as a permeable reactive barrier (PRB) to remove phenol from contaminated shallow groundwater was investigated. Batch tests were performed to characterize the equilibrium sorption properties of GDAS and sandy soil in phenol-containing aqueous solutions. The Langmuir isotherm model gives a better fit for the sorption data of phenol by GDAS and soil than other models under the studied conditions. One-dimensional column experiments were performed at a pilot scale, and an integrated model based on the solution of an advection-reaction-dispersion mass balance equation, using the finite-element method, was developed to study the space and time normalized concentration of phenol within groundwater. Numerical and experimental results proved that the PRB plays a potential role in the restriction of the contaminant plume migration. Also, these results showed that the removal of phenol by PRB was increased as function of its thickness and that the barrier starts to saturate with contaminant as a function of the travel time. However, a good agreement between the predicted and experimental results was recognized with the root-mean squared error (RMSE) not exceeding 0.0460 and Nash-Sutcliffe efficiency not less than 0.9201. [ABSTRACT FROM AUTHOR]