Effect of processing time on removal of harmful emerging salt pollutants from saline-sodic soil during electrochemical remediation
Introduction
During the last years, the planet earth has been facing serious, harsh and hostile changes, including soil salinization and proliferation of harmful salts pollutants. The high toxicity of these species is damaging badly the environment, public health, agriculture productivity and civil engineering facilities (Li et al., 2014; Allbed et al., 2018; Zörb et al., 2019). Recent studies have reported that currently 75 countries are affected by soil salinity (Amini et al., 2016). The total salinized areas have been estimated to one billion hectares worldwide, roughly 10 times the surface of a country similar to Venezuela or else 20 times the surface of France (Shrivastava and Kumar, 2015; Ivushkin et al., 2017). Moreover, current reports state that more than 50% of cultivable lands would be affected by salinity by the year 2050 (Shrivastava and Kumar, 2015; Machado and Serralheiro, 2017; Yue et al., 2019). The origin of this hazard can be related to geogenic or anthropogenic activities, known as primary and secondary salinization, respectively (Shrivastava and Kumar, 2015). In term of primary salinity, the global warming, low rainfall rates, high temperatures and evapotranspiration will reduce drastically the leachability and lixiviation of salts, increasing hence salt concentration within the solid matrix to toxic levels. The secondary salinity is caused by human activities, such as irrigation with salt-rich water and random use of chemical fertilizers (Waleeittikul et al., 2019). Worldwide, nearly 95 million hectares are suffering from primary salinity, while 77 million hectares of soils are under secondary salinization (Amini et al., 2016). The most harmful emerging salt pollutants (HESPs) are sodium (Na+), chloride (Cl−), nitrate (NO3−), sulfate (SO42−), calcium (Ca2+), potassium (K+) and magnesium (Mg2+). High concentration of HESPs will negatively affects the ecosystem biodiversity, crop yield, public health as well as urban and rural infrastructures (Cassaniti et al., 2012; Zhang et al., 2018). In terms of agricultural productivity, high levels of HESPs would hinder the crop growth, owing to the high toxicity of these chemicals, causing a net increase of the osmotic pressure, cellular damage and nutriments uptake (Rahneshan et al., 2018). Excessive concentrations of these compounds in the food chain and fresh water may harm the human health, causing several diseases, such as methemoglobinemia (MetHb), stomach cancer, infant mortality and birth malformations (Choi et al., 2012). The increase of the soil salinity has a serious impact on civil engineering infrastructures. High amount of unconfined HESPs within the medium induces numerous hazards on the physico-chemical properties of the soil, generating hence surface crusting, soil erosion, water logging, permeability degradation, weak bearing capacity and low shear strength (Wilson, 2003; Jayasekera, 2007). Furthermore, the high toxicity of these species allow significant degradations in concrete structures and reinforced iron rebars, causing real damages, such as deterioration of structures stability, sustainability and lifespan (Kim et al., 2010). On the other hand, soil salinization is causing losses of millions dollars annually, which may negatively affect the future prosperity of a country’s economy. Thereby, it decreases the social income and benefits (Pearson-Stuttard et al., 2018). To mitigate this hazard, many desalinization and remediation methods have been applied, such as soil substitution, chemical amendment, controlled irrigation and cultivation of salt-tolerant plants. However, recent studies reported that these techniques are expensive, time consuming and mostly ineffective (Choi et al., 2012). Electrochemical remediation (ECR) is a novel, environmental friendly and cost effective technique with promising applicability against contamination and salinity problems (Yola et al., 2014; Figueroa et al., 2016; Göde et al., 2017; Vizcaíno et al., 2018; Fallgren et al., 2018; Cameselle and Gouveia, 2018; Cameselle and Reddy, 2019; Méndez et al., 2019). The removal of HESPs is based on the applicability of an electrical gradient via two electrodes inserted into the soil sample. The electrical current promotes the leachability, mobilization and transportation of the HESPs out of the soil, owing to three main mechanisms, known as electrophoresis, electro-migration (EM) and electro-osmosis flow (EOF) (Faisal et al., 2018). Electrolysis reactions allow the formation of pH gradient, with an acidic and a basic medium at the anode and cathode regions, respectively. The acid pH would enhance desorption, solubilization and mobilization of HESPs, facilitating hence their removal. Electro-migration process allows the migration of charged species toward the oppositely charged electrodes (Asavadorndeja et al., 2005; Cameselle, 2015). The EOF is known as the movement of water from the anode to the cathode. The water flux, contributes significantly on the transport of the cationic HSEP and thereby their removal from the anode toward the cathode. Recently, numerous studies have investigated the applicability of the ECR to remediate saline soils. Jo et al. (2015), reported that the ECR is a promising technique for reclaiming saline soils, reaching removal efficiency above 96% for chloride and nitrate ions. An in-situ research was successfully conducted by Choi et al. (2016). The authors state a significant improvement in crop productivity. Han et al. (2017) has contested that the ECR was extremely relevant in reclaiming greenhouses soils, achieved a removal efficiency of 99% for nitrate and sodium ions. Although these researches have proven the effectiveness of ECR for reclaiming saline soils, very limited studies have been reported on the effect of processing time on remediation of high alkaline saline-sodic soils. The aim of this research was to investigate the influence of treatment time on the removal and extraction of HSEPs, including sodium, potassium, calcium, magnesium, chloride and sulfate, in order to remediate saline-sodic soils as well as mitigation of salinity danger. Therefore, it will contribute on the enhancement of agriculture yield, managing civil engineering infrastructures and improving the socio-economic prosperity. The originality of the present study is to bring a contribution to the explanation on the versatile behavior of HESPs under different treatment times. The present study will provide valuable comprehensive support for further successful applicability of the ECR technology on reclaiming of salt-stressed soils in semi-arid areas.
Section snippets
Saline- sodic soil samples
Soil samples were collected from Ain Nouissy, in the North West part of Algeria. The study area has known severe salinity and sodicity problems over last years. According to the Köppen-Geiger classification, the climate of the studied region is described as “BSK-CSA type” which is classified as a semi-arid climate. The area is characterized with cold-dry winter and warm-dry summer climate. The high temperatures and low rainfall rate prevent leaching of salts, allowing salt accumulation on the
Electrical current and electroosmotic flow (EOF) variations
The electrochemical treatment induces several changes within the soil matrix, including the electrical intensity and the generation of a net flow toward the cathode. Fig. 2 shows the variation of the electrical current and EOF over processing time.
The electric current showed a similar trend for both tests, 3 and 5 days. During the first 15 h, the intensities exhibit a sharp increase until reaching a peak of 275 and 300 mA during 3 and 5 days, respectively. Then, the intensities drop down
Conclusion
The objective of this research was to assess the effect of processing time on remediation of saline-sodic soil, for enhancing agriculture productivity and civil engineering uses. Two duration times were selected in aim to evaluate their influence of removal of seven different harmful salt pollutants.
The increase of processing time has been shown very efficient in removal of monovalent cationic (sodium and potassium) and anionic salts (nitrate and chloride). Higher duration periods allow better
CRediT authorship contribution statement
Mohammed Mustapha Bessaim: Writing - original draft, Methodology, Visualization, Investigation, Formal analysis. Hanifi Missoum: Supervision, Conceptualization, Writing - review & editing. Karim Bendani: Supervision. Nadia Laredj: Supervision. Mohamed Said Bekkouche: Supervision, Writing - review & editing.
Declaration of competing interests
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgment
Authors would like to thank the chemical department for their help in this research. The authors, therefore, acknowledge with thanks the environmental research council for their technical support.
References (42)
- et al.
Electrokinetic remediation: basics and technology status
J. Hazard Mater.
(1995) - et al.
Development and enhancement of electro-osmotic flow for the removal of contaminants from soils
Electrochim. Acta
(2012) Enhancement of electro-osmotic flow during the electrokinetic treatment of a contaminated soil
Electrochim. Acta
(2015)- et al.
Electrokinetic remediation for the removal of organic contaminants in soils
Current Opinion in Electrochemistry
(2018) - et al.
Removal characteristics of salts of greenhouse in field test by in situ electrokinetic process
Electrochim. Acta
(2012) - et al.
A novel electrochemical sensor based on calixarene functionalized reduced graphene oxide: application to simultaneous determination of Fe (III), Cd (II) and Pb (II) ions
J. Colloid Interface Sci.
(2017) - et al.
Effects of electrolyte characteristics on soil conductivity and current in electrokinetic remediation of lead-contaminated soil
Separ. Purif. Technol.
(2014) - et al.
Study of electrochemical removal of phenanthrene in bentonite clay by physicochemical indicators
Separ. Purif. Technol.
(2019) - et al.
Feasibility of coupling permeable bio-barriers and electrokinetics for the treatment of diesel hydrocarbons polluted soils
Electrochim. Acta
(2015) - et al.
Soil salinity: a serious environmental issue and plant growth promoting bacteria as one of the tools for its alleviation
Saudi J. Biol. Sci.
(2015)
Application of a crustacean bioassay to evaluate a multi-contaminated (metal, PAH, PCB) harbor sediment before and after electrokinetic remediation using eco-friendly enhancing agents
Sci. Total Environ.
A sensitive voltammetric sensor for determination of Cd (II) in human plasma
J. Mol. Liq.
Electrokinetic remediation of heavy metals contaminated kaolin by a CNT-covered polyethylene terephthalate yarn cathode
Electrochim. Acta
Removal of fluorine from red mud (bauxite residue) by electrokinetics
Electrochim. Acta
Soil salinity and vegetation cover change detection from multi-temporal remotely sensed imagery in Al Hassa Oasis in Saudi Arabia
Geocarto Int.
Salt-affected soils, reclamation, carbon dynamics, and biochar: a review
J. Soils Sediments
Electroremediation of Zn (II) contaminated soft bangkok clay with cathode depolarization technique
Institute of Lowland Technology, Saga University
Sodic-saline soil remediation by electrochemical treatment under uncontrolled pH conditions
Arabian Journal of Geosciences
Electrochemical Remediation for Contaminated Soils, Sediments and Groundwater
The response of ornamental plants to saline irrigation water
Electrokinetic restoration of saline agricultural lands
J. Appl. Electrochem.
Cited by (21)
Participation influence of silicate on the temporal and spatial distribution of chloride electromigration in the electrokinetics of municipal solid waste incineration fly ashes
2023, Journal of Environmental Chemical EngineeringEnhanced remediation of hydrocarbons contaminated soil using electrokinetic soil flushing – Landfarming processes
2022, Bioresource Technology ReportsCitation Excerpt :Based on the electrolysis reaction of water in the anode and cathode, pH near the anode will turn very acidic because it is filled with H+ ions. In contrast, the pH at the cathode becomes very alkaline due to excessive OH− ions (Bessaim et al., 2020). Soil pH changes occur rapidly depending on the total applied voltage and electrolyte type presented in the anode or cathode chamber.
An overview of in-situ remediation for nitrate in groundwater
2022, Science of the Total EnvironmentCitation Excerpt :Oxidation in electrolytic reaction causes a dramatic change in pH, which reduces the pH of the anode area, and increases the pH of the cathode area. H+ and OH− is then moved under the effect of electromigration, forming acidic and alkaline zone in aquifer (Bessaim et al., 2020). H+ in acidic zone promotes dissolution of soil minerals, increases the ionic intensity and conductivity of pore groundwater and thus enhancing the remediation efficiency.