| 1. |
- Abd Ali, Ziad T., et al.
(författare)
-
Predominant mechanisms for the removal of nickel metal ion from aqueous solution using cement kiln dust
- 2020
-
Ingår i: Journal of Water Process Engineering. - : Elsevier BV. - 2214-7144. ; 33
-
Tidskriftsartikel (refereegranskat)abstract
- The experimental methodology achieved in the present study signified that the adsorption and precipitation were main mechanisms occurred together in the removal of nickel from aqueous solution by sorption using cement kiln dust (CKD) byproduct as sorbent. Finding the contribution of each mechanism in the removal process and derivation an analytical model for finding the portion of precipitation were the focal points of this work. Results proved that pure precipitation was increased with the increase of CKD dosage and metal concentration where total removal (adsorption-precipitation) ranged from 45 to 100%. The SEM micrographs of the CKD sorbent before and after sorption process certified that there was crystal precipitates on the surface of the CKD. Also, these graphs in combination with FT-IR tests proved that [Ni(OH2)n]+2 (n=4-6) species were bonded with CKD and insoluble hydroxide species may be precipitated onto the CaO surfaces by co-precipitation, while K–O, Si-O and Ca-O groups enhanced the adsorption mechanism.
|
|
| 2. |
- Rahi, Muna A., et al.
(författare)
-
Biochemical performance modelling of non-vegetated and vegetated vertical subsurface-flow constructed wetlands treating municipal wastewater in hot and dry climate
- 2020
-
Ingår i: Journal of Water Process Engineering. - : Elsevier BV. - 2214-7144. ; 33
-
Tidskriftsartikel (refereegranskat)abstract
- Wastewater treatment and subsequent effluent recycling for non-drinking purposes such as irrigation contributes to the mitigation of the pressure on freshwater resources. In this study, two vertical sub-surface flow constructed wetland (VSSF-CW) pilot plants were operated to treat municipal wastewater and their effluents were reused for irrigation purposes. One of the wetlands was vegetated with Phragmites australis (Cav.) Trin. ex Steud. (common reed) to compare its efficiency of pollutant removals with the non-vegetated system, which had the same design. COMSOL Multiphysics 3.5a was operated for the Activated Sludge Model 2 (ASM2) to predict the chemical oxygen demand (COD) and ammonia-nitrogen (NH4-N) concentrations. The effluent quality of both treatment systems was assessed for several parameters. Computer simulations show a good compliance between the measured and predicted values of COD and NH4-N for the vegetated system. The calibrated model could be effectively used to predict the behaviours of those parameters as a function of time. Moreover, the effluents of both vegetated (VFp) and non-vegetated (VF) VSSF-CW were significantly (p < 0.05) improved compared to influent. Significant (p < 0.05) effects due to the presence of P. australis were observed for removals of total suspended solids (TSS), 5-day biochemical oxygen demand (BOD5), COD, NH4-N and ortho-phosphate-phosphorus (PO4-P). However, significant increases (p < 0.05) were noted for electrical conductivity (EC), total dissolved solids (TDS), nitrate-nitrogen (NO3-N) and sulphate (SO4) of both effluents compared to the raw wastewater. Except for EC, NH4-N and SO4, all water quality parameters complied with irrigation water standards.
|
|
| 3. |
- Saad, Noora, et al.
(författare)
-
Development of Bi-Langmuir model on the sorption of cadmium onto waste foundry sand : Effects of initial pH and temperature
- 2020
-
Ingår i: Environmental Engineering Research. - : Korean Society of Environmental Engineers. - 1226-1025 .- 2005-968X. ; 25:5, s. 677-684
-
Tidskriftsartikel (refereegranskat)abstract
- The present study develops the sorption model for simulating the effects of pH and temperature on the uptake of cadmium from contaminated water using waste foundry sand (WFS) by allowing the variation of the maximum adsorption capacity and affinity constant. The presence of two acidic functional groups with the same or different affinity is the basis in the derivation of the two models; Model 1 and Model 2 respectively. The developed Bi-Langmuir model with different affinity (Model 2) has a remarkable ability in the description of process under consideration with coefficient of determination > 0.9838 and sum of squared error < 0.08514. This result is proved by FTIR test where the weak acids responsible of cadmium ions removal using WFS sorbent can be represented by surface silanol (O-H) functional groups.
|
|
| 4. |
- Ahmed, Dooraid N., et al.
(författare)
-
Waste foundry sand/MgFe-layered double hydroxides composite material for efficient removal of Congo red dye from aqueous solution
- 2020
-
Ingår i: Scientific Reports. - USA : Nature Publishing Group. - 2045-2322. ; 10, s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- We aimed to obtain magnesium/iron (Mg/Fe)-layered double hydroxides (LDHs) nanoparticles-immobilized on waste foundry sand-a byproduct of the metal casting industry. XRD and FT-IR tests were applied to characterize the prepared sorbent. The results revealed that a new peak reflected LDHs nanoparticles. In addition, SEM-EDS mapping confirmed that the coating process was appropriate. Sorption tests for the interaction of this sorbent with an aqueous solution contaminated with Congo red dye revealed the efficacy of this material where the maximum adsorption capacity reached approximately 9127.08 mg/g. The pseudo-first-order and pseudo-second-order kinetic models helped to describe the sorption measurements, indicating that the physical and chemical forces governed the removal process.
|
|
| 5. |
- Alshammari, Musa, et al.
(författare)
-
Synthesis of a Novel Composite Sorbent Coated with Siderite Nanoparticles and its Application for Remediation of Water Contaminated with Congo Red Dye
- 2020
-
Ingår i: International Journal of Environmental Research. - Switzerland : Springer. - 1735-6865 .- 2008-2304. ; 14:2, s. 177-191
-
Tidskriftsartikel (refereegranskat)abstract
- Re-use of the byproduct wastes resulting from different municipal and industrial activities in the reclamation of contaminated water is real application for green projects and sustainability concepts. In this direction, the synthesis of composite sorbent from the mixing of waterworks and sewage sludge coated with new nanoparticles named “siderite” (WSSS) is the novelty of this study. These particles can be precipitated from the iron(II) nitrate using waterworks sludge as alkaline agent and source of carbonate. Characterization tests using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) mapping revealed that the coating process was correctly achieved and siderite nanoparticles were planted on the surface of the composite sorbent. Interaction between Congo Red dye and composite sorbent was evaluated through a set of batch tests under the variation of agitation time, pH of aqueous solution, and sorbent dosage. The results proved that the prepared sorbent had a high ability in the treatment of water contaminated with Congo Red dye in comparison with previous studies and the maximum adsorption capacity reached to maximum value i.e. 9416 mg/g. The sorption process was governed by electrostatic attractions; however, Sips and Pseudo-second-order models described this process with coefficient of determination greater than 0.99.
|
|
| 6. |
- Faisal, Ayad A.H., et al.
(författare)
-
COMSOL multiphysics 3.5a package for simulating the cadmium transport in the sand bed-bentonite low permeable barrier
- 2020
-
Ingår i: Journal of King Saud University - Science. - Netherlands : Elsevier. - 1018-3647. ; 32:3, s. 1944-1952
-
Tidskriftsartikel (refereegranskat)abstract
- Here, batch study for Iraqi bentonite-cadmium aqueous solution interaction was conducted with condi- tions of contact time ::; 120 min, sorbent dosage from 0.05 to 1 g per 100 mL and shaking speed from 50 to 300 rpm for initial concentration of 50 mg/L with initial pH of 3 to simulate the acetogenic phase in the sanitary landfill. The best conditions were 1 h, 0.7 g/100 mL and 250 rpm, respectively to obtain the high- est removal (90%). The sorption data were well formulated by Freundlich and Langmuir models with determination coefficient (R2) 2: 0.98 and sorption capacity of 145.3 mg/g; so, the removal process gov- erned by the physico-chemical forces. The average coefficient of the hydraulic conductivity was found equal to 1.98 x 10-10 m/s and this is suitable for low permeable barrier (LPB). Finally, the predictions of COMSOL package were presented satisfactory simulation for the cadmium concentrations within two-dimensional physical model packed with sand aquifer and Iraqi bentonite. Two configurations of LPB were evaluated for restriction of contaminant front migration and the results proved that the sur- rounding of the location required to protect it from three sides against to the flow direction can be more dependable from continuous configuration.
|
|
| 7. |
- Faisal, Ayad A.H., et al.
(författare)
-
Using different materials as a permeable reactive barrier for remediation of groundwater contaminated with landfill’s leachate
- 2020
-
Ingår i: Desalination and Water Treatment. - : Desalination Publications. - 1944-3994 .- 1944-3986. ; 175, s. 152-163
-
Tidskriftsartikel (refereegranskat)abstract
- 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 compar-ison 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 3.938mg/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.
|
|
| 8. |
- Naji, Laith A., et al.
(författare)
-
Modification of Langmuir model for simulating initial pH and temperature effects on sorption process
- 2020
-
Ingår i: Separation science and technology (Print). - UK : Taylor & Francis. - 0149-6395 .- 1520-5754. ; 55:15, s. 2729-2736
-
Tidskriftsartikel (refereegranskat)abstract
- The present study modifies the sorption isothermfor simulating the influences of initial pH and temperature variations on thecadmium sorption from contaminated water using waste foundry sand based on Langmuir,Freundlich and Temkin models. Results proved that the Langmuir expression is ableto adopt these effects by relating sorption capacity and affinity constantswith pH and temperature of aqueous solution through exponential relationships (determinationcoefficient = 0.9375). The present model is assumed that the sorption process occursthrough acidic functional groups and this is consistent with FTIR outputs. Interactionof cadmium/WFS is found to be exothermic by thermodynamic analysis.
|
|
