Enhanced removal of humic acid from aqueous solution by combined alternating current electrocoagulation and sulfate radical

Rajaei, Fatemeh; Taheri, Ensiyeh; Hadi, Sousan; Fatehizadeh, Ali; Amin, Mohammad Mehdi; Rafei, Nasim; Fadaei, Saeid; Aminabhavi, Tejraj M.

doi:10.1016/j.envpol.2021.116632

Cited by 35 publications

(6 citation statements)

References 31 publications

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“…Rajaei et al managed to reach a 90%+ elimination rate of humic acid within 25 min. They used a combination of Fe and Al as the anode and the cathode, but when the Fe was both anode and cathode, the elimination rate was 99.4% with the same conditions [205]. They kept the current density at 4.5 mA/cm 2 ; when the electrodes were Al, the elimination efficiency was 96.1% [205].…”

Section: Humic Acidsmentioning

confidence: 99%

A Comprehensive Review of the Developments in Electrocoagulation for the Removal of Contaminants from Wastewater

Ammar,

Yousef,

Mahmoud

et al. 2023

Separations

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Water organic pollution has become a major issue. A large number of people suffer from the decline in water quality. In addition, polluted water can lead to health problems or excessive deaths. In this regard, an increasingly important method for efficient water treatment is electrocoagulation (EC), the technology that encompasses a small equipment size combined with a simple operation compared to other water treatment methods. The importance of EC is especially accentuated by the recent decarbonization efforts due to the increasing availability of renewable electricity systems. This review provides an overview of the most recent developments in EC technology as it pertains to wastewater treatment. The EC is preferred for organic wastewater treatment over other traditional treatment methods due to its easy setup and low material costs. Moreover, the EC is very powerful in destabilizing organic impurities by charge neutralization and then coagulating to form flocs. In addition, EC has shown high efficiency not only in removing various organic pollutants but also in emerging persistent contaminants, such as microplastics. For these reasons, the EC mechanisms and related functional modalities are reviewed, as well as extensive details are provided on the diversity of the removed contaminants. Overall, this review provides significant new knowledge of interest for environmental chemical researchers in particular and engineers in general on the details of the EC technology for wastewater treatment and water purification.

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Section: Humic Acidsmentioning

confidence: 99%

A Comprehensive Review of the Developments in Electrocoagulation for the Removal of Contaminants from Wastewater

Ammar,

Yousef,

Mahmoud

et al. 2023

Separations

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“…(5) In terms of the effect of the solution pH, Figure 3 indicates that acidic conditions favor the elimination of CPX. This may be due to two reasons: (i) under acidic conditions, the decomposition of S 2 O 8 2À into radicals is favored (Equations ( 6) and ( 7)) (Rajaei et al 2021); and (ii) CPX has two acid dissociation constants (pK a ), one at pH ∼2.56 and the other at pH ∼6.88 (Legnoverde et al 2014), which implies that at solution pH in the range 2.56 to 6.88 the charge of the CPX molecule would be neutral (isoelectric point ∼4.5) (Figure 1) while at more acidic conditions it would be in cationic form and its reactivity would be higher promoting its elimination. Water Science & Technology Vol 00 No 0, 5…”

Section: Optimization Of Reaction Conditionsmentioning

confidence: 99%

Cephalexin removal by persulfate activation using simulated sunlight and ferrous ions

Perdomo

Minota

Zúñiga-Benítez

et al. 2021

Water Science and Technology

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This study presents the main results related to the use of activated persulfate (PS) in the elimination of the beta-lactam antibiotic cephalexin (CPX). Experiments were done using K2S2O8 and simulated sunlight. A face-centered central composite experimental design was used to analyze the effects of the solution pH and the PS concentration on the reaction, and to determine the optimized conditions that favor the CPX elimination. The results indicated that the removal of CPX is promoted by an acidic pH and under the higher evaluated PS dose (7.5 mg L−1). CPX total removal was achieved in 30 min. The analysis of the effect of the pollutant initial concentration indicated that a pseudo-first order kinetic model can be used to describe the reaction. Likewise, the use of Fe2+ ions for PS activation (in the dark) was evaluated and allowed to establish that a higher concentration of ions favors the pollutant removal. Control tests and under the presence of scavenger agents indicated that both HO• and SO4−• radicals would be present in the solution and promote the CPX elimination. The assessment of the solution dissolved organic carbon, nitrates and sulfates was also carried out, and indicated that a portion of the organic matter was mineralized.

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“…HA is the main cause of water color and odor. Furthermore, HA can interact with toxic organic compounds and heavy metal ions and therefore influence the distribution and migration of organic matter and metal ions by hydrophobic distribution, adsorption, charge transfer and static repulsion (Ren et al 2017;Rajaei et al 2021). More seriously, during drinking water disinfection, HA can react with chlorine to produce various by-products which are potentially carcinogenic, deformed and mutated-like (Bond et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Adsorption of humic acid fractions by a magnetic ion exchange resin

Ding

Wang

et al. 2022

Water Science and Technology

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Natural organic matter in waters varies in different fractions. To better understand the removal of different fractions by a magnetic ion exchange (MIEX) resin and the mechanism behind it, this study investigated adsorption kinetics, equilibrium and thermodynamics of humic acid (HA) fractions with different hydrophilic-hydrophobic properties and molecular weights on MIEX resin through a series of batch experiments. MIEX resin can effectively remove approximately 40% of hydrophilic and 30% of hydrophobic HA components, as well as approximately 44% of molecular weight (MW) <10 kDa to some degree. The removal efficiency of HA fractions by MIEX resin reduced with the increase of pH from 6 to 9. Adsorption kinetics of different HA fractions on MIEX resin fitted the pseudo-second-order model well. With the increase of MW of HA from <1 kDa to >10 kDa, the time to reach adsorption equilibrium reduced from 180 to 120 min. It took more time for the hydrophilic fractions (140 min) to reach the equilibrium than for hydrophobic HA fractions (120 min). The Sips model fitted the adsorption equilibrium data of HA fractions on MIEX resin well. It was revealed that the adsorption of HA fractions on MIEX resin was spontaneous, endothermic and an entropy driven process, and the chemisorption might dominate the adsorption of HA components on MIEX resin. This study is of great significance to the design of magnetic ion exchange resin reactors and the optimization of operational parameters for the removal of natural organic matter with different hydrophilic-hydrophobic properties and molecular weights in different water sources.

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Enhanced removal of humic acid from aqueous solution by combined alternating current electrocoagulation and sulfate radical

Cited by 35 publications

References 31 publications

A Comprehensive Review of the Developments in Electrocoagulation for the Removal of Contaminants from Wastewater

A Comprehensive Review of the Developments in Electrocoagulation for the Removal of Contaminants from Wastewater

Cephalexin removal by persulfate activation using simulated sunlight and ferrous ions

Adsorption of humic acid fractions by a magnetic ion exchange resin

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