| 1. |
- Pulkka, Susanna, et al.
(författare)
-
Electrochemical methods for the removal of anionic contaminants from water - A review
- 2014
-
Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 132, s. 252-271
-
Forskningsöversikt (refereegranskat)abstract
- Different electrochemical methods such as electrocoagulation, electro-oxidation, and electroreduction have been found effective for the removal of various anionic pollutants from water and wastewater. Electrochemical processes can transform contaminants directly or manipulate the redox condition of the environmental matrix to achieve adaptive condition. This review focuses on the removal of different anions, including cyanide, fluoride, nitrate, nitrite, phosphate, and sulfate, from water by electrocoagulation, electro-oxidation, and electroreduction methods. Optimum treatment conditions for studied anions in each electrochemical method are discussed. An overview of electrochemical methods used for anions removal together with specific applications and experimental results are presented and discussed. It is evident from the literature reviewed that these methods have shown considerable potential for the removal of anionic pollutants from water. However, the most challenging issue in this research area is to find out the practical application of these methods on commercial scale, leading to the improvement of pollution control. (C) 2014 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Al-Hamdi, Abdullah M., et al.
(författare)
-
Efficient photocatalytic degradation of phenol in aqueous solution by SnO2:Sb nanoparticles
- 2016
-
Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 370, s. 229-236
-
Tidskriftsartikel (refereegranskat)abstract
- Photodegradation of phenol in the presence of tin dioxide (SnO2) nanoparticles under UV light irradiation is known to be an effective photocatalytic process. However, phenol degradation under solar light is less effective due to the large band gap of SnO2. In this study antimony (Sb) doped tin dioxide (SnO2) nanoparticles were prepared at a low temperature (80 degrees C) by a sol-gel method and studied for its photo catalytic activity with phenol as a test contaminant. The catalytic degradation of phenol in aqueous media was studied using high performance liquid chromatography and total organic carbon measurements. The change in the concentration of phenol affects the pH of the solution due to the by-products formed during the photo-oxidation of phenol. The photoactivity of SnO2:Sb was found to be a maximum for 0.6 wt.% Sb doped SnO2 nanoparticles with 10 mg L-1 phenol in water. Within 2 h of photodegradation, more than 95% of phenol could be removed under solar light irradiation.
|
|
| 3. |
- Al-Hamdi, Abdullah M., et al.
(författare)
-
Gadolinium doped tin dioxide nanoparticles : an efficient visible light active photocatalyst
- 2015
-
Ingår i: Journal of Rare Earths. - : Elsevier. - 1002-0721 .- 2509-4963. ; 33:12, s. 1275-1283
-
Tidskriftsartikel (refereegranskat)abstract
- Photocatalytic degradation of phenol with sol-gel prepared rare earth doped tin dioxide (SnO2) nanoparticles was reported. Gadolinium doped tin dioxide (SnO2:Gd) nanoparticles were found to absorb higher visible light compared to lanthanum, neodymium and cerium doped materials that were studied in detail. Photocatalytic degradation of phenol under artificial white light and sunlight in the presence of SnO2: Gd nanoparticles was studied with high performance liquid chromatography (HPLC), capillary electrophoresis (CE), total organic carbon (TOC) measurements and the determination of chemical oxygen demand (COD). Clear correlations between the results obtained from these multiple measurements were found, and a kinetic pathway for the degradation process was proposed. Within 150 min of solar irradiation, the TOC of a 10 ppm phenol solution in water was reduced by 95%-99%, thus demonstrating that SnO2: Gd nanoparticles are efficient visible light photocatalysts.
|
|
| 4. |
- Bhatnagar, Amit, et al.
(författare)
-
An overview of the modification methods of activated carbon for its water treatment applications
- 2013
-
Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 219, s. 499-511
-
Forskningsöversikt (refereegranskat)abstract
- Activated carbon has been recognized as one of the oldest and widely used adsorbent for the water and wastewater treatment for removing organic and inorganic pollutants. The application of activated carbon in adsorption process is mainly depends on the surface chemistry and pore structure of porous carbons. The method of activation and the nature of precursor used greatly influences surface functional groups and pore structure of the activated carbon. Therefore, the main focus of researchers is to develop or modifies the activation/treatment techniques in an optimal manner using appropriate precursors for specific pollutants. In recent years, emphasis is given to prepare the surface modified carbons using different procedures to enhance the potential of activated carbon for specific contaminants. Various methods such as, acid treatment, base treatment, impregnation treatment, ozone treatment, surfactant treatment, plasma treatment and microwave treatment have been studied to develop surface modified activated carbons. In this paper, these modification methods have been reviewed and the potential of surface modified activated carbons towards water treatment has been discussed. This review article is aimed at providing precise information on efforts made by various researchers in the field of surface modification of activated carbon for water pollution control. (C) 2012 Elsevier B.V. All rights reserved.
|
|
| 5. |
- Bhatnagar, Amit, et al.
(författare)
-
Valorization of solid waste products from olive oil industry as potential adsorbents for water pollution control-a review
- 2014
-
Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 21:1, s. 268-298
-
Forskningsöversikt (refereegranskat)abstract
- The global olive oil production for 2010 is estimated to be 2,881,500 metric tons. The European Union countries produce 78.5 % of the total olive oil, which stands for an average production of 2,136,000 tons. The worldwide consumption of olive oil increased of 78 % between 1990 and 2010. The increase in olive oil production implies a proportional increase in olive mill wastes. As a consequence of such increasing trend, olive mills are facing severe environmental problems due to lack of feasible and/or cost-effective solutions to olive-mill waste management. Therefore, immediate attention is required to find a proper way of management to deal with olive mill waste materials in order to minimize environmental pollution and associated health risks. One of the interesting uses of solid wastes generated from olive mills is to convert them as inexpensive adsorbents for water pollution control. In this review paper, an extensive list of adsorbents (prepared by utilizing different types of olive mill solid waste materials) from vast literature has been compiled, and their adsorption capacities for various aquatic pollutants removal are presented. Different physicochemical methods that have been used to convert olive mill solid wastes into efficient adsorbents have also been discussed. Characterization of olive-based adsorbents and adsorption mechanisms of various aquatic pollutants on these developed olive-based adsorbents have also been discussed in detail. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.
|
|
| 6. |
- Hokkanen, Sanna, et al.
(författare)
-
Adsorption of hydrogen sulphide from aqueous solutions using modified nano/micro fibrillated cellulose
- 2014
-
Ingår i: Environmental technology. - : Informa UK Limited. - 0959-3330 .- 1479-487X. ; 35:18, s. 2334-2346
-
Tidskriftsartikel (refereegranskat)abstract
- In the present study, microfibrillated cellulose (MFC) was modified by aminopropyltriethoxysilane (APS), hydroxy-carbonated apatite (HAP), or epoxy in order to produce novel nanostructured adsorbents for the removal of hydrogen sulphide (H2S) from the aqueous solutions. Structural properties of the modified MFC materials were examined using a scanning electron microscope, Fourier transform infrared spectroscopy and acid/base titration. These methods were used to verify the presence of nanostructures on the adsorbents surfaces as well as functionalities suitable for H2S adsorption. Adsorption of H2S by prepared adsorbents was investigated in batch mode under different experimental conditions, i.e. varying pH and H2S concentrations. H2S uptake was found to be 103.95, 13.38 and 12.73mg/g by APS/MFC, HAP/MFC and epoxy/MFC, respectively from 80mg/L H2S solution. The equilibrium data were best described by the Langmuir isotherm for HAP/MFC and APS/MFC and the Sips isotherm for epoxy/MFC.
|
|
| 7. |
- Kumar, Eva, et al.
(författare)
-
Interaction of inorganic anions with iron-mineral adsorbents in aqueous media - A review
- 2014
-
Ingår i: Advances in Colloid and Interface Science. - : Elsevier BV. - 0001-8686 .- 1873-3727. ; 203, s. 11-21
-
Forskningsöversikt (refereegranskat)abstract
- A number of inorganic anions (e.g., nitrate, fluoride, bromate, phosphate, and perchlorate) have been reported in alarming concentrations in numerous drinking water sources around the world. Their presence even in very low concentrations may cause serious environmental and health related problems. Due to the presence and significance of iron minerals in the natural aquatic environment and increasing application of iron in water treatment, the knowledge of the structure of iron and iron minerals and their interactions with aquatic pollutants, especially inorganic anions in water are of great importance. Iron minerals have been known since long as potential adsorbents for the removal of inorganic anions from aqueous phase. The chemistry of iron and iron minerals reactions in water is complex. The adsorption ability of iron and iron minerals towards inorganic anions is influenced by several factors such as, surface characteristics of the adsorbent (surface area, density, pore volume, porosity, pore size distribution, pH(pzo) purity), pH of the solution, and ionic strength. Furthermore, the physico-chemical properties of inorganic anions (pore size, ionic radius, bulk diffusion coefficient) also significantly influence the adsorption process. The aim of this paper is to provide an overview of the properties of iron and iron minerals and their reactivity with some important inorganic anionic contaminants present in water. It also summarizes the usage of iron and iron minerals in water treatment technology. (C) 2013 Elsevier B.V. All rights reserved.
|
|
| 8. |
- Kumar, Rakesh, et al.
(författare)
-
State-of-the-art of research progress on adsorptive removal of fluoride-contaminated water using biochar-based materials : Practical feasibility through reusability and column transport studies
- 2022
-
Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 214
-
Tidskriftsartikel (refereegranskat)abstract
- Fluoride (F-) is one of the essential elements found in soil and water released from geogenic sources and several anthropogenic activities. Fluoride causes fluorosis, dental and skeletal growth problems, teeth mottling, and neurological damage due to prolonged consumption, affecting millions worldwide. Adsorption is an extensively implemented technique in water and wastewater treatment for fluoride, with significant potential due to efficiency, cost-effectiveness, ease of operation, and reusability. This review highlights the current state of knowledge for fluoride adsorption using biochar-based materials and the limitations of biochar for fluoride-contaminated groundwater and industrial wastewater treatment. Biochar materials have shown significant adsorption capacities for fluoride under the influence of low pH, biochar dose, initial concentration, temperature, and co-existing ions. Modified biochar possesses various functional groups (-OH, -C=C, -C-O, -CONH, -C-OH, X-OH), in which enhanced hydroxyl (-OH) groups onto the surface plays a significant role in fluoride adsorption via electrostatic attraction and ion exchange. Regeneration and reusability of biochar sorbents need to be performed to a greater extent to improve removal efficiency and reusability in field conditions. Furthermore, the present investigation identifies the limitations of biochar materials in treating fluoride-contaminated drinking groundwater and industrial effluents. The fluoride removal using biochar-based materials at an industrial scale for understanding the practical feasibility is yet to be documented. This review work recommend the feasibility of biochar-based materials in column studies for fluoride remediation in the future.
|
|
| 9. |
- Levchuk, Irina, et al.
(författare)
-
Overview of technologies for removal of methyl tert-butyl ether (MTBE) from water
- 2014
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 476, s. 415-433
-
Forskningsöversikt (refereegranskat)abstract
- Wide use of methyl tert-butyl ether (MTBE) as fuel oxygenates leads to worldwide environment contamination with this compound basically due to fuel leaks from storage or pipelines. Presence of MTBE in drinking water is of high environmental and social concern. Existing methods for MTBE removal from water have a number of limitations which can be possibly overcome in the future with use of emerging technologies. This work aims to provide an updated overview of recent developments in technologies for MTBE removal from water. (C) 2014 Elsevier B.V. All rights reserved.
|
|
| 10. |
- Li, Changbai, et al.
(författare)
-
Separation and concentration of rare earth elements from wastewater using electrodialysis technology
- 2021
-
Ingår i: Separation and Purification Technology. - : ELSEVIER. - 1383-5866 .- 1873-3794. ; 254
-
Tidskriftsartikel (refereegranskat)abstract
- Rare earth elements (REEs) including Scandium (Sc) are critical raw materials which are greatly needed in the advancement of many modern technologies. Due to the problems associated with the primary extraction of mining ores, the procurement of Sc and REEs from the secondary resources are currently explored adopting the principle of sustainability and circular economy. Herein, for the first time, the Electrodialysis (ED) technology based on electrochemical membrane separation process is successfully applied to separate and concentrate REEs from the diluted aqueous system. The overall performance of ED process in the recovery of Sc3+ ions from the wastewater was assessed by applied current, voltage, feed concentration, feed pH, co-ion competition and the overall energy consumption of the process. The REE recovery using the ED process was subjected to systematic investigations using both chronopotentiometric and chronoamperometric analyses. The results showed that ED process could be very promising in the recovery of Sc3+ ions (similar to 99.52% removal) from the diluted wastewater, consuming the energy of only 0.26 kWh/m(3) when operated at constant voltage mode (Sc3+ concentration of 20 ppm, pH 4, 1 h).
|
|
