1 Introduction

Heavy metals are naturally occurring micro-elements that are essential for life, and when present beyond the recommended threshold by regulatory bodies (Table 1), they become hazardous to humans and other organisms [1,2,3,4,5]. Sources of heavy metal pollutants from wastewater include (but are not limited to) industrial, mining, agricultural activities, and waste disposal [6,7,8,9]. Membrane filtration, ion exchange, biological methods, and chemical precipitation are conventional methods used for the exclusion of heavy metal pollutants from wastewater. However, most of these techniques come with high costs, incomplete ion removal, sludge generation, and the extra cost of sludge disposal and membrane fouling [10]. Therefore, alternative advanced wastewater treatment approaches devised include adsorption, electrochemical, membrane, and advanced oxidation processes-based wastewater treatment approaches [11,12,13,14,15,16]. Selection of these methods relies on various factors, including concentration and heavy metal types present, wastewater volume, and the desired level of treatment efficiency among others. The effectiveness and long-term viability of heavy metals removal methods are being improved by ongoing studies and technological developments, opening the door to more effective and ecologically friendly wastewater treatment options.

Table 1 Summarized regulatory limits of heavy metals
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Studies have shown that combining two methods for the removal of pollutants from wastewater offers several significant advantages such as high efficiency, synergistic effects, lower energy consumption, reduces chemical usage and operational costs [17,18,19]. Integrated approaches enhance the overall efficiency of the treatment process by leveraging the strengths of each method. For instance, EC effectively destabilizes and coagulates metal particles, while AD provides a high surface area for capturing these particles, leading to more comprehensive pollutant removal [20]. The dual approach in wastewater treatment not only provides greater flexibility in handling varying wastewater compositions but also enhances the robustness and resilience of the treatment system to fluctuations in pollutant loads. Therefore, the combined use of EC and AD represents a promising strategy for more efficient and sustainable heavy metal removal from wastewater.

As reviewed extensively elsewhere, adsorption (AD) and electrocoagulation (EC) are key methods applied separately to treat different wastewater [21,22,23,24]. The EC and AD systems have applications in wastewater treatment processes, albeit existence of certain drawbacks. Particularly, primary challenge of the EC lies in its energy consumption, particularly when treating highly concentrated effluents that require a substantial current to generate sufficient coagulant for treatment. Although, adsorption, is known for its adaptable design and operational flexibility, the process may also encounter limitations. For example, adsorbent saturation and the competitive effects of certain compounds are among the adsorption bottlenecks. A viable solution to address these constraints and leverage the strengths of both processes is their integration with other methods, providing an effective approach to wastewater treatment [25]. In this mini-review work, we have given the overview of adsorption, electrocoagulation and their simulations combination for the removal heavy metal contaminants from wastewater sources.

1.1 Electrocoagulation technique

The electrochemical processes can be primarily categorized into electrocoagulation (EC), electroflotation (EF), Electrooxidation (EO), and ion exchange (IE) [21]. Research show that these methods can be coupled with other wastewater treatment approaches either sequentially, concurrently or consequentially to augment electro-adsorption processes. Indeed, as reviewed extensively, electrocoagulation has been combined with adsorption to remove organic pollutant from wastewater [27,28,29,30,31,32]. Noteworthy, most of these studies are narrowed towards synthetic effluents, constraining their applications in real-life settings [33]. Electrochemical process as such electrocoagulation technique uses electric currents to remove suspended, dissolved pollutants, or emulsified from water [34, 35].

In the EC method, steel (iron) or aluminum electrodes are used as electrodes given their reliability and non-toxicity properties, and the mechanism involved is illustrated by Eqs. (1) (2) and (3) [36]. The passing of an electric current through a solution containing heavy metals results to precipitation that can be easily removed as sludge [37,38,39]. This technique has shown promise in the removal of heavy metal contaminants due to its capacity to generate coagulants in situ and efficiency [40,41,42]. More prominently, electrocoagulation offers several advantages over conventional chemical coagulation or chemical flocculation. Firstly, as no chemicals are introduced during the process, there exist zero risk of secondary pollution from chemical concentrations, unlike in chemical coagulation or chemical flocculation methods. Additionally, the gas bubbles generated in EC aid in lifting pollutants to the surface, simplifying their collection. The operational simplicity of EC equipment enables easy automation of the process. Moreover, EC-treated wastewater yields clear, colorless, and odorless water, while the flocs produced are larger and more stable than those from chemical coagulation or chemical flocculation, facilitating their separation during filtration. Electrocoagulation also results in significantly less sludge volume, which is both more stable and non-toxic [36] Furthermore, even the smallest colloidal particles are effectively removed by EC due to the accelerated collision facilitated by the applied electric current. However, EC presents certain drawbacks that include the requirement for frequent replacement of sacrificial anodes due to their dissolution into the solution, potentially leading to increased operational costs [43, 44]. Additionally, the occurrence of cathode passivation can diminish the efficiency of the EC process and the high current required generating sufficient coagulant for the treatment [45], impacting its overall effectiveness. Moreover, in regions with limited access to affordable electricity, the operational expenses associated with EC can become prohibitive, posing a challenge to its widespread adoption [36]. To overcomes some of these limitations, electrode passivation which entails adding aggressive ion, alternating current operation, polarity reversal operation, ultra-sonication, chemical and mechanical cleaning of electrodes, and hydrodynamic scouring. Still, each pathway has hitches, such as being costly, generating hazardous materials and sludge accumulation [46]. Hence, the application of EC procedure in the removal of pollutant from wastewater is still not well developed for large scale applications. More importantly, exploring into alternative solutions is an important scientific goal in wastewater treatment.

$${\text{Metal}} \to {\text{Metal}}^{{{\text{n}} + }} + {\text{ne}}^{ - }$$
(1)
$${\text{2H}}_{{2}} {\text{O(1)}} + {\text{2e}}^{ - } \to {\text{H}}_{{2}} ({\text{g}})$$
(2)

Cations released by anode destabilize colloidal particles and as well generate hydroxide complex metal ions (coagulants), which then react with negatively charged pollutants existing in wastewater as:

$${\text{Metal}}^{{{\text{n}} + }} + {\text{nOH}} \to {\text{Metal}}\left( {{\text{OH}}} \right)_{{\text{n}}} \left( {\text{s}} \right)$$
(3)

Several studies have been brought forward to describe wastewater treatment via electrocoagulation processes (Table 2). Numerous studies have used the electrocoagulation technique (EC) to successfully remove soluble heavy metals pollutants from various wastewaters [38, 47, 48], such as zinc [49], nickel [50], mercury [51] among others. Specifically, the usefulness of electrocoagulation in the removal of heavy metals is demonstrated by a number of recent studies. An extensively reviewed, Cd(II) and Pb(II) could be removed from wastewater using an EC system using a Fe-Al anode and a stainless steel cathode, whereas, Cu(II) and Zn(II) could be removed from wastewater using an aluminum electrode at high efficiency rates [48]. Also, studies on the application of a three-dimensional graphene-modified paper electrode for the removal of Cr(VI) has been explored in an effort to improve the efficacy of electrocoagulation technology [52]. This study reported reduced energy consumption compared to traditional EC systems.

Table 2 Selected examples of electrocoagulation process used for the removal of heavy metals pollutants
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1.2 Adsorption techniques

Although a number of wastewater processes have been documented, adsorption is still simple, adaptable, practical, insensitive to obnoxious substances, and commercially viable approach. Numerous low-cost adsorbents (Table 3), such as nanomaterial [59, 60] activated carbon [61], natural zeolites [62, 63] and agro-waste biochar from banana peel [64], corncob [65], grapefruit peel [66], sugarcane bagasse [67], potato peel [68], rice straw [69], orange peel [70], wheat stem [71] and among others. Overall, absorbents can also be classified as polymeric based adsorbents which offer a versatile approach to heavy metal ion removal, utilizing synthetic materials with tailored functional groups such as poly(acrylic acid) (PAA), poly(amidoxime), and poly(hydroxamic acid) to selectively bind metal ions through chelation and ion exchange mechanisms [72]. Similarly, industrial by-product adsorbents, including metal hydroxide sludge, fly ash, and red mud, repurpose waste materials for cost-effective heavy metal removal. Additionally, natural minerals based adsorbents like silica, zeolite, and montmorillonite offer inherent adsorption properties, providing sustainable solutions for environmental remediation. Chitosan, a natural biopolymer, showcases potential for water purification through chelation of heavy metal ions. Each category presents unique advantages, contributing to effective and sustainable methods for heavy metal ion removal in various applications [72]. Notably, adsorption processes are hindered by costs, adsorbent saturation, selectivity and the competitive effects of specific chemicals.

Table 3 Examples of low-cost adsorbents used in the adsorption process in removal of heavy metal ions
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The most often used adsorbent is activated carbon, which produces the greatest results but is very costly in terms of production and regeneration [73, 74]. In adsorption, a solution becomes adsorbed on the surface of an adsorbent and occurs in two ways: physio-sorption, in which adsorbate attaches to adsorbent via van der Waals forces, which is a weak, reversible, and endothermic process, and chemi-sorption, which is an irreversible, selective, and exothermic process [75]. Adsorption mechanisms for removal of heavy metals from wastewater are illustrated in Fig. 1 [76,77,78,79].The adsorption process is described by isotherms which represent the estimated amount the solute that is adsorbed on the surface of the adsorbent per unit mass as a function of equilibrium concentration at a constant temperature. The adsorption process is described by the most widely used isotherms, namely Freundlich and Langmuir, Tables 4 and 5 [22].

Fig. 1
figure 1

Adsorption mechanism for heavy metals removal wastewater

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Table 4 Equations of adsorption isotherms
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Table 5 Kinetic models investigated in this study
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Adsorption processes has been used to remove of heavy metal ions from waste water, such as adsorptive removal of Cr (IV) from aqueous solutions by adsorption using adsorbents from hazelnut shell [89]. Compared to other similar studies, this was found to be more efficiency than coconut shell and wood adsorbents[90] with removal of between 58.5–87.6 mg/g, respectively. As reviewed by Hussain et al. [61], activated carbon prepared from wood saw dust to remove Cr (VI) from wastewater exhibited adsorption capacity of Cr(VI) 44 mg/g at an optimum pH 2.0, compared to activated carbon from coconut shell, sugarcane bagasse, coconut tree saw dust. Based on most reviewed literature and studies on the separate application of adsorption and electrocoagulation, we report that adsorbents have limited efficiency compared with the use of electrochemical method in the removal of heavy metal pollutants. Generally, the combination of electrocoagulation and adsorption methods is a potential method for eliminating heavy metal contaminants from wastewater, and the mechanism involve in adsorption (Fig. 1) is very crucial.

1.2.1 Isotherms and kinetics

Previous studies have proposed numerous isotherms and kinetic [91,92,93,94] however, only Langmuir and Freundlich adsorption isotherms have been described in EC-ADS systems. In practice, both Langmuir and Freundlich models are used, often in combination, to interpret experimental data and gain insights into the adsorption behavior of different systems. Aware of the reported limitations associated with isotherm parameters [95,96,97], the assessment of other parameters that affect EC-ADS process could be very scientifically interesting.

The following Langmuir [98], and Freundlich [99, 100] adsorption isotherms (Tables 4, 5) have been used to describe in the removal of heavy metals by EC-ADS process.

The parameters qe and qm (mg/g) correspond to the quantity of adsorbed ions per unit mass of adsorbent and the optimum amount of ions per unit mass necessary for a full layer on the surface of the adsorbent, respectively. The Ce mirrors the adsorbate's titre at equilibrium (mg/L). KL denotes the Langmuir equilibrium factor (L/mg), whilst n and KF are Freundlich constant which describe the extent of adsorption and the non-linear link between metal concentrations in solution and adsorption.

In this setting, qe and qt (mg/g) describe the equilibrium and time-dependent functions of heavy metal adsorption, accordingly. k1 signifies the pseudo-first-order rate constant (1/min), whereas k2 depicts the pseudo-second-order rate constant (g/mg.min). The Elovich equation's coefficients are β and α. β denotes the desorption constant (g/mg) and α defines the initial sorption rate. Kid clarifies the intra-particle diffusion rate constant (g/mg min1/2), whilst c is the intercept from the plot of qt versus t1/2.

1.3 Main application of EC-AD combined processes in the removal heavy metal pollutants from wastewater

Recently, interest in electrochemical-adsorption combined process have generated interest as evidently shown by registered patents in last decade [101]. Electrical potential is applied during the adsorption process in the EC-AD combined process. This combined approach, which uses a device with several electrodes coupled to an external circuit and combines adsorption with electrochemical concept design. Through electrical links, the potentiostat supply the working, reference, and counter electrodes with electrical impulses [102], serving as source of the current and voltage to the electrolytic cells. The electrolyte solution's constituent parts are adsorbed onto the working electrode during this process. By creating a double layer contact between the electrode and the solution, electro-adsorption works. This process is driven by a number of interactions, such as dipole and electrostatic interactions, to increase the rate and capacity of adsorption. Surface features, area, microstructure, pore size distribution, solution state, and electrode material properties are some of the variables that affect the EC-AD capacity. The technique lowers operating costs by prolonging the adsorbent regeneration life[101].The combined electrochemical-adsorption is a modified EC system introduced to enhance removal of chemical oxygen demand (COD), inorganic salts, antibiotics, dyes, colloidal particles, and turbidity pollutants [103]. Moreover, our literature review identified limited studies that have employed electrochemical-adsorption methods to remove heavy metals. For example, a study extensively reconnoitered the use of manganese oxide (birnessite-type) for synergistic removal of Cd(II) and As(V) from wastewater, shown the possibility of using electrosorbents in EC-AD process [104]. Orescanin et al. [105] suggested a novel electroplating wastewater treatment approach via integration of EC with Fe and Al electrodes with ozonation system, resulting to high efficiency (~ 97%) in the removal of Pb. In another scenario, Ferniza-García et al. [106] explored the elimination of heavy metal contaminants from simulated mining water by integrating EC with aluminum electrodes with phytoremediation supported by a conventional power supply. As we observed, limited attention has been directed towards understanding integrated electrochemical-adsorption proces, particularly when coupled with low-cost organic absorbents (Table 3). Currently, different adsorbents including AC, carbon nanotubes, bio-sorbents and low-cost adsorbents (agricultural wastes, industrial by-products, sands and clays) may be employed [107]. The effect of a few adsorbent types on EC-AD approaches on kinetics including pseudo-first order, pseudo-second order, and intra-particle diffusion have been reported [108]. Therefore, our work outline the application and selected parameters that affect electrocoagulation–adsorption methods. In the EC-AD combined system, the AD and EC can be used simultaneously, either in separate or combined system vessels.

Coupling of AD and EC processes refer to the solution for solving their limitations while advantaging from their potential. Moreover, the combination of these two processes offers the benefits of process intensification, such as a smaller unit footprint, increased versatility, and greater mobility. Additionally, the integration reduces operating costs and energy consumption, and the use of low-cost materials lowers investment costs. These advantages make this process particularly attractive for small industries. The EC coupled with adsorption has been used to remove target pollutants [109], however no inclusive literature has been devoted to understand its application in removal of heavy metal ions in wastewater treatment settings. A variety of electrode and adsorbent combinations have been employed in combined EC and AD processes to treat diverse wastewaters (Table 6). This process’ characteristic, its versatility increase in dealing with specific pollutant problems’ removal.

Table 6 Application of adsorption- electrocoagulation for the elimination of heavy metal pollutants from wastewaters
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Narayanan and Ganesan, [110] in their study used granular activated carbon adsorption coupled with batch electrocoagulation (EC) using an Al–Fe electrode pair to remove Cr(VI) from synthetic effluents. The key mechanisms in the removal of Cr(VI) were found to be the combined effects of chemical precipitation, co-precipitation, sweep coagulation, and adsorption. Comparing the results to the traditional EC technique, it was found that the use of an adsorbent improved the Cr(VI) removal efficiency, requiring lower current intensities and shorter operating time spans.

Ali et al. [1] used a combined EC-AD system for the removal of heavy metal pollutants from industrial wastewater was developed based on a bipolar configuration. This system used Al as the electrode and slag as the adsorbent. The removal efficiency was recorded as 99%, 91%, and 99% for Fe, Zn, and Cu, accordingly. The synergistic effects of electrokinetic treatment and adsorption were responsible for this efficiency. Analysis via XRF, SEM, FTIR, and PSA confirmed the enhanced removal efficiency attributed to EC. Freundlich isotherms were observed for Fe and Zn, while Cu removal did not follow a specific isotherm. Chemisorption was identified as the predominant removal mechanism for all metals. As a single-step, low-cost treatment method for removing trace heavy metals from wastewater that adheres to circular economy principles, this creative integrated approach has a lot of promise.

Hussin et al. [111] removed Pb(II) from aqueous solutions using an integrated method that included solar combined EC-AD procedures with a removal efficiency of 99.88%. The following settings were found to be ideal for maximal Pb(II) removal (99.88%): pH 6.01, starting Pb(II) concentration of 15.00 mg/L, and adsorbent dosage of 2.50 mg/L compared with single methods. Due to the low adsorbent usage, this combination method offers great removal efficiency and cost-effectiveness, surpassing individual electrocoagulation and adsorption treatments. Using low-cost and sustainable solar energy, it shows robustness and success in treating wastewater contaminated with heavy metals. Although further study is required to optimize and scale-up the process for industrial use, continuous operation utilizing solar energy has promise for large-scale applications.

Electrocoagulation combined with adsorption processes holds immense promise for efficiently treating wastewater contaminated with diverse pollutants, leveraging the synergistic effects of electrochemical coagulation and adsorption. However, as these processes are scaled-up, a spectrum of opportunities and challenges emerges. Enhanced treatment efficiency and versatility in heavy metal pollutant removal mark key opportunities, alongside the potential for cost-effectiveness and environmental sustainability through reduced chemical usage, low energy cost and sludge generation. For example, Hussin et al. [111], integrated the use solar in EC-ADS processes for Pb removal from aqueous solution. The energy consumption of the combined system, estimated at 0.045 kWh/m3, underscores its sustainability and cost-effectiveness, supported by previous studies [112, 113]. However, challenges such as maintaining electrode and adsorbent stability, managing energy consumption, optimizing processes, and ensuring regulatory compliance remain a bottleneck in the large scale-up application of EC-ADS process. Albeit the presence of a literature review on EC-ADS, There is a clear need to bridge the gap in addressing these challenges through the deployment of robust technological innovations and operational strategies. This is crucial for effectively implementing this technology on a larger scale and making substantial contributions to sustainable wastewater management practices across diverse industrial sectors.

1.4 Parameters that affect the EC-ADS efficiency in the removal of heavy metals from wastewater

1.4.1 Adsorbent dosages

Adsorbent doses influence the removal efficiency of heavy metal contaminants during the ADS/EC combined process. For example, in AGWTR experiments, the efficiency removal for Cu2+ and Ni2+ is augmented by the adsorbent dosage increase [102]. The ions in the solutions interacted with the ADS-binding sites resulting to higher removal efficiencies as previously studied [1, 117,118,119]. Hussin et al. [111] described that the higher adsorbent dosages increased Pb(II) removal efficiency, aligning with the premise that active sites of adsorbent may effectively adsorb more pollutants from the solution.

1.4.2 Energy considerations

The electric current density is a critical parameter in the EC-AD approaches, as it influences the generation of coagulant dosage rate, gas bubbles, and floc growth and size, which are essential for effective wastewater treatment [120, 121]. Current density has a major impact on mass transfer at the electrodes and solution mixing, which are both essential for the efficient removal of pollutants. Increasing the current density improves the mass transfer rates and improves mixing, which leads to higher removal efficiencies of Fe2+, Zn2+, and Cu2+ by the EC-AD process [1]. Also, This improvement may be explained by variations in floc size and development, as well as, higher rates of coagulant and bubble generation [42]. In the ADS/EC (AGWTR) system, current density has a major effect on solution mixing and mass transfer at the electrodes. Cu2 + and Ni2 + removal is reduced and anode dissolution is modest as a result of the low current density. On the contrary, owing to the faster generation of hydroxides through co-precipitation and enhanced dissolution of the iron electrode material, stronger current densities result in higher removal efficiencies for both metal ions [102].

1.4.3 Electrolysis time

Electrolysis time affects the efficiency of water and wastewater treatment, and inferred from contact period between the metal ions and the adsorbents in ADS/EC methods, The removal efficiency of heavy metals varied with time, the longer treatment periods improve the efficacy of removal by increasing metal hydroxide formation [42]. Similarly, in the exclusion of pollutant by AGWTR system, the longer adsorption contact times led to increased removal of copper (Cu2 +) and nickel (Ni2 +) due to active surface sites on the adsorbent material. For instance at 120 min, 1 g of adsorbent removed 73.51% of Cu2 + and 66.01% of Ni2 + . Additionally, the coagulant generated from iron electrodes in ADS coupled with EC increases with reaction time, enhancing removal efficiencies through sweep coagulation and co-precipitation. The peak removal efficiency for Cu2 + and Ni2 + occurs at 30 min, where 100% and 99.98% of respective ions were removed, facilitated by iron (III) hydroxide "sweep flocs" with large surface areas conducive to the adsorption of pollutants from wastewater. Overall, the Cu2+ and Ni2+ removal was directly proportional to the adsorption contact time which is clarified by the high availability of active surface sites on the adsorbents [102, 122].

1.4.4 Concentration of hydrogen ions (pH)

The pH influence the removal of heavy metal pollutants during EC-AD process [102]. For example, the pH value of 2–8 favored the removal of Cu2+ from simulated wastewater in the EC-AD simultaneous process. Specifically, the highest removal efficiency was observed at pH 4.0 due to the presence of Fe(OH)3, which is influenced by the pH and Fe3+ concentration. The removal efficiency of Cu2+ was higher than Ni2+ in both AD and AD/EC processes. Maintaining a low initial pH, such as 4.0, was found to enhance the Cu2+ and Ni2+ removal without the need for additional chemicals. In another study, the Pb2+ precipitate in solutions with a pH > 7, implying that the removal efficiency of these pollutants was similarly influenced by pH [1]. This underscores the importance of controlling pH in the treatment of wastewater.

1.4.5 Adsorption isotherms

This review indicates that when Cu2+ and Ni2+ were removed from synthetic wastewater using AGWTR coupled with AD and EC, the adsorption isotherms indicated that Langmuir had a superior fit with higher correlation coefficients than Freundlich. On the AGWTR surface, monolayer adsorption with maximum adsorption capabilities was suggested using the Langmuir model. Overall, the computed adsorption isotherms revealed that heavy metals could be readily adsorbed during the EC-AD process [102]. In the removal of Pb2+ by combined solar EC-AD process, pseudo-first-order kinetics analysis produced a fit experimental data [111]. The results indicated that Pb(II) is adsorbed and removed from aqueous solutions more quickly in the combined treatment procedure than in individual treatments. This implies that the combined system of solar EC-AD outperforms processes that were carried out individually.

From literature review, the study suggests a deeper consideration of process parameters concerning potential scale-up for the EC-AD (Electrocoagulation and Adsorption) method in removing heavy metals from wastewater. For examples, most study used model solution which may not give true about the applicability of this method although promising. Our study found that the efficacy of EC-AD is influenced by different parameters: adsorbent dosages, current density, electrolysis time, and pH. Generally, the study found that adsorbent dosages affect removal efficiency by increasing interaction with metal ions, while current density influences mass transfer rates and mixing, crucial for pollutant removal [1]. Electrolysis time affects removal efficacy through prolonged contact periods. While, pH plays a significant role, with optimal values favoring metal ion removal. Adsorption isotherms, particularly Langmuir, suggest efficient heavy metal adsorption during the EC-AD process, although recent work have reported flaws associated with isotherms parameters [95,96,97]. In summary, we suggest, a thorough re-evaluation of these parameters to optimize the process for potential scale-up is necessary for ensuring effective and efficient heavy metal removal from wastewater. The main challenges to the scale-up of integrated electrocoagulation-adsorption strategies for the removal of heavy metal pollutants from wastewater include optimizing the design and operation of large-scale electrocoagulation reactors to ensure efficient removal of heavy metals while minimizing operational costs. Additionally, achieving consistent and reliable adsorption performance over extended periods poses a challenge, as factors such as adsorbent regeneration and stability need to be addressed. Furthermore, the scalability of these integrated systems may be hindered by the variability of wastewater composition and heavy metal concentrations, necessitating robust monitoring and control mechanisms. Moreover, addressing potential environmental impacts and ensuring compliance with regulatory standards at scale are important considerations. Finally, economic viability and the availability of suitable adsorbents in large quantities can also influence the successful scale-up of electrocoagulation-adsorption strategies for heavy metal removal from wastewater.

2 Conclusion

This mini-review explores the application and influencing factors of the AD-EC combined process for heavy metal ion removal from different wastewaters. Wastewater treatment is a critical aspect of environmental protection. This review explores the integration of the electrocoagulation-adsorption process as an effective and sustainable approach for heavy metal ion removal. Adsorption using various adsorbents provides extraordinary surface area and affinity for heavy metal ions, whereas electrocoagulation ensures efficient coagulation and subsequent separation of the formed flocs. One of the approaches to sidestep the limitations of individual wastewater treatment methods is the integration of EC with AD processes, allowing optimal removal of pollutants from wastewater. This review highlights that combined AD-EC approaches exhibit high efficiency in heavy metal removal from diverse wastewater sources, although the design, optimization, and scaling up of this method for broader application in wastewater treatment remains a topic for further exploration. Future studies should aim to bridge the gap between laboratory-scale experiments and real-world applications. While many studies have established the efficacy of EC with AD processes in controlled settings, there is a need for more research conducted in actual wastewater treatment plants or field sites. This would provide valuable insights into the scalability, reliability, and cost-effectiveness of these technologies in practical scenarios.