•Electrochemical oxidation of pyrite occurred by two reaction pathways.•At potential of 0.50 V, electrochemical oxidation of pyrite was diffusion-limited.•At potential of 0.60 V, amorphous S8 was slowly converted to crystalline S8.•S8 was difficult to be oxidized electrochemically even at high potential.•Oxidation of pyrite was inhomogeneous on electrode surface.The oxidation of pyrite under acidic conditions, an important process leading to the formation of acid mine drainage, has been the subject of intense research yet remains incompletely understood. In this study, the mechanism of the electrochemical oxidation of pyrite in a pH 2 electrolyte was investigated using electrochemical techniques. The morphological changes and oxidation products of pyrite were studied using atomic force microscopy (AFM), Raman spectroscopy (RS), and X-ray photoelectron spectroscopy (XPS). At low potential of 0.50 V, electrochemical oxidation of pyrite was diffusion-limited due to a sulfur-rich layer (S0) that formed and covered the pyrite surface, resulting in surface passivation. As the potential increased to 0.60 V, diffusion-limitation and surface passivation of pyrite oxidation ceased due to the conversion of amorphous elemental sulfur (S8) to crystalline S8, resulting in the previously covered active sites being re-exposed which allowed continued oxidation of pyrite. At higher potentials of 0.70 and 0.80 V, more S8 and polysulfides (Sn2−), together with an iron-rich layer composed of Fe(OH)3, FeO and Fe2O3, formed and accumulated on the pyrite surface. These products led to a decreased rate of oxidation rather than a complete passivation of the surface. AFM imaging revealed that surface roughness increased with oxidation potential and that the oxidation of the pyrite surface was inhomogeneous. These findings provide further insight into the physical and chemical changes that pyrite undergo during electrochemical oxidation, which deepens our understanding of this important process.

•HPLC is an efficient technique to detect the S0 and SnO62 −.•S0 is formed definitely during pyrite oxidation process.•Some species of SnO62 − also formed and their concentrations increased.•ferrooxidans promoted the pyrite oxidation.•ferrooxidans accelerated KFe3(SO4)2(OH)6) and FeOOH formation.The intermediate sulfur species of pyrite chemical and biological oxidation have been the subject of controversy for some time, especially the question of whether or not elemental sulfur (S0) and polythionates (SnO62 −) are formed during the oxidation process. Acidithiobacillus ferrooxidans (A. ferrooxidans), one of the most common sulfur-oxidizing bacterial strains, has been shown to remarkably accelerate pyrite oxidation. In this study, the intermediate products of pyrite oxidation with and without A. ferrooxidans present were compared by employing different analytical techniques; i.e., high performance liquid chromatography (HPLC), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). The HPLC results showed that the concentrations of S0, S3O62 −, S4O62 −, S5O62 − and S6O62 − increased during pyrite oxidation process in the presence of A. ferrooxidans. Secondary minerals jarosite (KFe3(SO4)2(OH)6) and iron(III) oxide-hydroxide (FeOOH) were also detected by XRD and XPS. Without A. ferrooxidans, S0 was also formed and along with S3O62 −, S4O62 − and S5O62 − but only at very low concentrations at the end of the experiment. SEM micrographs further revealed that the pyrite was severely eroded by A. ferrooxidans and some spheroidal particles covered the surfaces of pyrite residues. These particles are most likely to be KFe3(SO4)2(OH)6 based on EDS analysis. The present study has quantitatively confirmed the presence of intermediate products of S0 and SnO62 − during pyrite oxidation, information that deepens our understanding of the mechanism of pyrite oxidation.

•Transmembrane transport of phenanthrene was stimulated by Tween80.•Tween80 induced the expression of peptidylprolyl isomerase to stabilize cell membrane.•Tween80 regulated abundances of proteins involved in intracellular metabolic pathways.•Multiple cellular mechanisms contributed to the increased phenanthrene biodegradation.Previous study concerning the effects of surfactants on phenanthrene biodegradation focused on observing the changes of cell characteristics of Sphingomonas sp. GY2B. However, the impact of surfactants on the expression of bacterial proteins, controlling phenanthrene transport and catabolism, remains obscure. To overcome the knowledge gap, comparative proteomic approaches were used to investigate protein expressions of Sphingomonas sp. GY2B during phenanthrene biodegradation in the presence and absence of a nonionic surfactant, Tween80. A total of 23 up-regulated and 19 down-regulated proteins were detected upon Tween80 treatment. Tween80 could regulate ion transport (e.g. H+) in cell membrane to provide driving force (ATP) for the transmembrane transport of phenanthrene thus increasing its uptake and biodegradation by GY2B. Moreover, Tween80 probably increased GY2B vitality and growth by inducing the expression of peptidylprolyl isomerase to stabilize cell membrane, increasing the abundances of proteins involved in intracellular metabolic pathways (e.g. TCA cycle), as well as decreasing the abundances of translation/transcription-related proteins and cysteine desulfurase, thereby facilitating phenanthrene biodegradation. This study may facilitate a better understanding of the mechanisms that regulate surfactants-enhanced biodegradation of PAHs at the proteomic level.

•The pollutant-degrading bacteria could be encapsulated into the bio-microcapsules.•Pyrene degradation rate by the cells was significantly increased by encapsulation.•Cells in the bio-microcapsules could endure high initial pyrene concentrations.•Cells in the bio-microcapsules could endure wider pH and temperature conditions.Biotechnology is considered as a promising technology for the removal of polycyclic aromatic hydrocarbons from the environment. Free bacteria are often sensitive to some biotic and abiotic factors in the environment to the extent that their ability to effect biodegradation of organic pollutants, such as polycyclic aromatic hydrocarbons, is hampered. Consequently, it is imperative to carry out investigations into biological systems that will obviate or aid tolerance of bacteria to harsh environmental conditions. Chitosan/alginate bio-microcapsules produced using layer-by-layer (LBL) assembly method were tested for pyrene (PYR) biodegradation under harsh environmental conditions. Morphology observation indicated that the flake bio-microcapsules could be successfully prepared through LBL assembly method. Surface analysis showed that the bio-microcapsules had large fractions of mesopores. The results of the biodegradation experiments revealed that the 95% of 10 mg L−1 PYR could be removed by the bacteria encapsulated chitosan/alginate bio-microcapsules in 3 days, which was higher than that of the free bacteria (59%). Compared to the free cells, the bacteria encapsulated chitosan/alginate bio-microcapsules produced 1–6 times higher PYR biodegradation rates at a high initial PYR concentration (50 mg L−1) and extremely low pH values (pH =3) or temperatures (10 °C or 40 °C), as well as high salt stress. The results indicated that bacteria in microcapsules treatment gained a much higher tolerance to environmental stress and LBL bio-microcapsule could be promising candidate for remediating the organic pollutants.Layer-by-layer assembly chitosan/alginate bio-microcapsules were prepared, and pyrene-degrading bacteria were successfully encapsulated into them. The microcapsule- encapsulated bacteria demonstrated immense environmental adaptability and excellent ability of pyrene degradation in high initial pyrene concentration, acidic, low temperature or high salt stress conditions.Download high-res image (165KB)Download full-size image

The cycling of Fe and Cr is intimately linked to the fate of schwertmannite in acid mine drainage (AMD) and acid sulfate soil (ASS) environments. Dissolved organic matter (DOM) can affect the stability of minerals and speciation, mobility and toxicity of heavy metals via redox reactions and complexation. However, knowledge about the fate of Fe and Cr upon reduction and complexation of CrO42 −-substituted schwertmannite by fulvic acid (FA) is poorly understood. In this study, experiments were devised to investigate the interaction between FA and schwertmannite, with major degeneration of the schwertmannite structure as well as the formation of secondary minerals. For CrO42 −-substituted schwertmannite, results indicated that the concentrations of total Fe and Cr in the solution were determined to be the maximum values at 360 h and 96 h, and then decreasing over the reaction time when FA was 10 mg/L at pH of 6.5. The characterization on the solid phase by X-ray diffraction, scanning electron microscopy and X-ray photo electron spectroscopy technologies revealed that goethite was the dominant newly secondary mineral phases which played a vital role in controlling the fate and transport of Fe and Cr. The possible mechanism was proposed to be synergistic effect including ligand-promoted and reduction. This study provides new insights into the understanding of trace element behavior in environments affected by DOM and also has guiding significance for Cr-contaminant remediation.

This study reports on the enhanced bioremediation of pyrene (PYR)-contaminated soil resulting from organisms immobilized in layer-by-layer (LBL) assembled microcapsules. The characterization by microscopy indicated that the shape of the microcapsule was like a flake with a diameter of 3–4 μm and that bacteria were encapsulated in the microcapsules. Soil remediation experiments revealed that PYR with an initial concentration of 100 mg kg−1 in dry soil could be 81% removed by an immobilized consortium (107 CFU g−1 in dry soil) in 40 days, while only 42% was removed by the free bacteria. Moreover, the LBL-immobilized cells could cause a significant increase in the biodiversity of the bacterial community, soil enzyme activity and the number of PYR-degrading bacteria in the soil, successfully accounting for accelerated PYR removal. Illumina MiSeq sequencing results showed that Proteobacteria and Actinobacteria were observed as the predominant groups during bioremediation in the LBL groups. The active uncultured bacteria belonged to Xanthomonadaceae, Planococcaceae, Pseudomonas, Mycobacterium, Sphingomonadaceae, Acinetobacter, Flavobacterium, Comamonadaceae, Bacillus, Sphingobacterium, Enterobacteriaceae, and Streptomyces, the latter two classes having rarely been associated with PAH-degrading activity. The results indicated that the LBL microcapsule treatment might be a potential bacteria immobilization option for soil bioremediation.

•C, N co-doped TiO2 nanotube arrays works as a photoanode in a PEC system.•Recombination of photo-generated holes and electrons were greatly reduced.•Synergetic effect was quantified in PEC degradation.•PEC oxidation and reduction abilities were enhanced in this study concurrently.Carbon and nitrogen were co-doped into TiO2 nanotube arrays (C–N-TNTAs) to extend their light response region using the chemical bath deposition method. The as-synthesized C–N-TNTAs were employed as the working anode in photoelectrochemical (PEC) experiments. Using the applied bias potential, the recombination of photo-generated holes and electrons was reduced significantly. The crystalline, optical properties, surface morphology, and structure of the C–N-TNTAs were characterized by XRD, UV–vis absorbance edges, SEM, and XPS, respectively. The XRD results showed the C–N-TNTAs were dominated by the anatase phase after sintering at 450 °C with significant visible light response. XPS analyses indicated nitrogen doping was mainly responsible for reducing the band gap as evidence of 0.82% N doping into the structure via the linkage of the TiON and NTiO bond. SEM images illustrated the diameter of the supported TiO2 nanotubes was approximately 90–100 nm with a length of approximately 400 nm. After carbon and nitrogen co-doping, the nanotubular structure of TiO2 nanotube kept its integrity with no significant morphological change, which was beneficial for PEC applications. The degradation efficiency of methyl orange (MO) was examined by photoelectrochemical, photocatalytic, electrochemical and photolysis methods for comparison in terms of pseudo-first-order reaction rate. The PEC method had the best MO degradation efficiency with a rate constant of 2.3 × 10−3 s−1 at a bias potential of 1.0 V (vs. SCE) under illumination, that was consistent with results of IPCE (%) measurements (the maximum IPCE up to 30.02% at 325 nm wavelength). The synergetic effect was quantified at current/time curves at bias potentials of 0.03 mA/0 V and 3.0 mA/1.0 V, respectively. Electrochemical impedance spectroscopy (EIS) measurements revealed the electron lifetime τel of photoexcited electrons in photoanodes was increased about 3.2 times after CN doping treatment. The bias potential could separate photo-generated holes and electrons effectively and enhance the electrochemical-oxidation of MO. Hydrogen generation was concurrently conducted in the cathodic chamber. After 180 min of reaction time, the amount of H2 reached 3.2 mmol by employing C–N-TNTAs as the photoanode.

•Saline surfactant shows lower CMC values than fresh surfactant.•The lower β values of saline surfactants, the higher pyrene solubilization.•STPP reduces surfactant sorption onto soil and enhances pyrene desorption.This study investigates the influence of salinity on micellar behavior, enhanced solubilization and desorption of pyrene within single and mixed saline anionic–nonionic surfactants. Various interaction parameters linked to the micellarization and solubilization process have been correlated through theoretical treatments to quantify micellar characteristics and solubilization capabilities of the systems. Results show that the experimental critical micelle concentration (CMC) values of the saline system were lower than that of non-saline system, indicating more attractive interactions of individual surfactants and higher stability of mixed micelles in the presence of salts. Pyrene solubility in saline surfactant solutions exceeded that in a non-saline solution. Less electrostatic repulsion of saline mixed micelles may be responsible for the reduced CMC of the mixed micelles, the increase of molar solubilization ratio (MSR) and micelle–water partition coefficient (Km). The saline micelles enhanced desorption of pyrene from kaolin-rich soil, and the pyrene desorption increased with the increase of salinity. Furthermore, the presence of salinity reduced the sorption of surfactant onto kaolin-rich soil; e.g. from 15.34 to 11.07 mg of surfactant/g of soil at a mass ratio of 5:5 mixture of anionic and nonionic surfactants. The results of this study provide new insights for estimating the utility of mixed surfactants treatments for soil remediation.

The efficiency of polysiloxane coating to suppress the pyrite oxidation under environmentally relevant conditions was investigated with electrochemical techniques. Cyclic voltammogram, Nyquist plot or Tafel test were preformed in the conditions of different polysiloxane proportions in modifying agent, pH values, Fe3+ concentrations and volumes of water impact. The increased proportion of polysiloxane in the modifying agent would enhance the protective effect of the coating. The modifying agent with the least proportion of polysiloxane was used in subsequent experiments to illustrate the excellent passivation of polysiloxane. The results indicated that coating on the pyrite had good protective effect to resist the oxidation of pyrite in the aggressive condition of pH 2. Moreover, there were no distinctive differences in coated pyrite behaviors during anodic oxidation in solutions with different pH values. Furthermore, in a wide range of Fe3+ concentrations, the coating on the pyrite still showed good effect to retard the pyrite oxidation. Finally, the coating on the pyrite possessed good washing durability. Therefore, polysiloxane coating had great potential to develop a new AMD suppression strategy.

Cellulose was isolated from corn stalk and modified by graft copolymerization to produce an absorbent material (AGCS-cell), which was characterized by scanning electron microscope and energy disperse spectroscopy (SEM–EDS), X-ray diffraction (XRD) and solid-state CP/MAS 13C NMR. The results showed that AGCS-cell had better adsorption potential for cadmium ion than unmodified cellulose because of the addition of functional groups (CN and OH groups) and the lower crystallinity. The Langmuir isotherms gave the best fit to the data and gave an adsorption capacity was 21.37 mg g−1, which was close to unpurified cellulose (AGCS) and reflected the feasibility of using AGCS-cell as an adsorbent to remove cadmium ions.Highlights► Cellulose was isolated from corn stalk further and produced efficient adsorbent. ► GE value and adsorption capacities of isolated cellulose were better. ► Adsorption ability of isolated cellulose are near to corn stalk copolymer. ► The R2 values for isolated cellulose in all isotherms were highest. ► Cellulose isolated from corn stalk was found to be a potential adsorbent.

The fusant strain (F14), which produced by protoplast fusion between Sphingomonas sp. GY2B (GenBank DQ139343) and Pseudomonas sp. GP3A (GenBank EU233280), was tested for phenanthrene biodegradation at 30 °C and pH of 7.0. The kinetics of phenanthrene biodegradation by F14 was investigated over a wide range of initial concentration (15–1,000 mg l−1). The rate and the extent of phenanthrene degradation increased with the increase of concentration up to 230 mg l−1, which indicated negligible inhibition effect at low concentrations. The non-competitive inhibition model was found to be fit for the process. GC–MS analysis showed that biodegradation of phenanthrene by F14 was via dioxygenation at both 1,2- and 3,4-positions and followed by 2-hydroxy-1-naphthoic acid and 1-hydroxy-2-naphthoic acid. The relative intensity of 2-hydroxy-1-naphthoic acid was approximately 3–4 times higher than that of 1-hydroxy-2-naphthoic acid, indicating the 2-hydroxy-1-naphthoic acid was the predominant product in the phenanthrene degradation by fusant strain F14.

Rice straw as a lignocellulosic agricultural residue was chemically converted into a strong basic anion exchanger (RS-AE). Epoxy and amino groups were introduced into raw rice straw by reaction with epichlorohydrin and trimethylamine after it was treated in sodium hydroxide solution. The exchangers were characterized by element analysis, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The results showed that total exchanger capacity of rice straw was increased by 1.32 mEq/g, and quaternary amino groups were formed on its new fibrous surface after modification. Batch adsorption experiments suggested RS-AE exhibits a much higher sulphate maximum adsorption capacity (74.76 mg/g) in contrast to that of raw straw (11.68 mg/g). The equilibrium data were described by Langmuir and Freundlich isotherm models, respectively, and were found to agree very well with the former. RS-AE also showed a good performance in regeneration cycles and a high selectivity for sulphate ions.

The electrochemical behavior of a pyrite electrode in a sulfuric acid solution with different concentrations of ferric iron (Fe3+) was investigated using electrochemical techniques including measurements of open circuit potential, cyclic voltammetry, Tafel polarization curves and electrochemical impedance spectroscopy (EIS). The results show that the pyrite oxidation process takes place via a two-step reaction at the interface of the pyrite electrode and the electrolyte, and that a passivation film composed of elemental sulfur, polysulfides, and metal-deficient sulfide is formed during the process of the first-step reaction. Ferric iron plays an important role in the dissolution of pyrite by enhancing the direct oxidation. The Tafel polarization curves indicate that the polarization current of the pyrite electrode increases with an increase in Fe3+ concentration. It has also been shown that the higher concentration of Fe3+, the more easily the pyrite can be transformed into the passivation region. Moreover, the EIS response is found to be sensitive to changes in Fe3+ concentration.

This study reported quantifications of fine particle bound trace metals and their potential health risks for residents in Guangzhou, a rapidly developing and most populated city in South China. The fine particle samples were collected from October 29th. to November 8th. of 2006 at two different elevations in a mainly residential area and analyzed for the total concentration of aluminum, iron, zinc, lead, manganese, copper, arsenic, chromium, nickel, cadmium, molybdenum and cobalt. Results showed that the fine particle concentrations ranged from 95.8μg/m3to 194.7 μg/m3 at the ground and 83.3-190.0 μg/m3 on the roof, which were much higher than the 24 h fine particle standard (35 μg/m3) recommended by USEPA. The total concentrations of zinc, lead, arsenic, chromium and cadmium in fine particle were 504.8, 201.6, 24.3, 7.7 and 4.4 ng/m3, respectively, which were comparable to other major cities of China, but much higher than major cities outside of China. A sequential extraction procedure was used to fractionate these fine particle bound metals into four different fractions. Results indicated that most toxic metals were mainly distributed in bioavailable fractions. For instance, about 91 % of cadmium, 85 % of lead and 74 % of arsenic were in bioavailable forms. Risk calculations with a simple exposure assessment model showed that the cancer risks of the bioavailable fractions of arsenic, chromium and cadmium were 3 to 33 times greater than usual goal, indicating serious health risks to the residents in this urban area.

Analytical methods of chloramphenicol in the aquaculture environment have been developed using high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry. The contents of chloramphenicol were determined using high-performance liquid chromatography for sediment and liquid chromatography-tandem mass spectrometry for fish and water collected from a freshwater aquaculture pond in China. Chloramphenicol in the water and sediment were 112.3 ng/L and 0.1957 mg/kg, respectively. The chloramphenicol residues in 3 kinds of fish, including carp, chub and grass carp were different. Only the muscle and head of grass carp were under the minimum required performance limit (0.3 μg/kg) and were safe to eat. The chloramphenicol in other tissues of grass carp, carp and chub exceeded the minimum required performance limit. The highest content of chloramphenicol was in the branchia of carp and the lowest was in the head of grass carp. The results showed the chloramphenicol in the aquaculture environment was serious, although the government of China had banned the use of chloramphenicol in aquaculture a few years ago.

Sites co-contaminated with organic and metal pollutants are common and considered to be a more complex problem as the two components often causes a synergistic effect on cytotoxicity. Phytoremediation has been proposed as a cost-effective technology for treating heavy metal or organic contamination and may be suitable for remediation of co-contaminated soil. This study investigated the concurrent removal of pyrene and cadmium in co-contaminated soil by growing maize in a pot experiment. At the end of 60 day culture, pyrene in spiked soil diminished significantly, accounting for 21–31 % of the initial extractable concentration in unplanted soil and 12–27 % in planted soil. With the increment of cadmium level, the residual pyrene both in unplanted and planted soil tended to increase. Although the presence of cadmium increased the accumulation of pyrene in maize, plant accumulation only account for less than 0.30 % of the total amount of the dissipated pyrene in vegetated soils. It implied that plant-promoted microbial biodegradation was the predominant contribution to the plant-enhanced dissipation of pyrene in co-contaminated soil. Unlike pyrene, heavy metal cadmium cannot be degraded. It was observed that maize can concurrently removed about on the average 0.70 % of the total cadmium amount in soil by plant uptake, but cadmium phytoextraction would be inhibited under contamination of pyrene. Maize CT38 can normally grow in the co-contaminated soil with high level cadmium and pyrene and can effectively remedy the sites co-contaminated with these two types of contamination, which suggest the possibility of simultaneous phytoremediation of two different contaminant types.

Three aerobic bacterial consortia GY2, GS3 and GM2 were enriched from polycyclic aromatic hydrocarbon-contaminated soils with water-silicone oil biphasic systems. An aerobic bacterial strain utilizing phenanthrene as the sole carbon and energy source was isolated from bacterial consortium GY2 and identified as Sphingomonas sp. strain GY2B. Within 48 h and at 30°C the strain metabolized 99.1% of phenanthrene (100 mg/l) added to batch culture in mineral salts medium and the cell number increased by about 40-fold. Three metabolites 1-hydroxy-2-naphthoic acid, 1-naphthol and salicylic acid, were identified by gas chromatographic mass spectrometry and UV–visible spectroscopy analysis. A degradation pathway was proposed based on the identified metabolites. In addition to phenanthrene, strain GY2B could use other aromatic compounds such as naphthalene, 2-naphthol, salicylic acid, catechol, phenol, benzene and toluene as a sole source of carbon and energy.

Soil contamination in the vicinity of the Dabaoshan Mine, Guangdong Province, China, was studied through determination of total concentrations and chemical speciation of the toxic metals, Cu, Zn, Cd, and Pb, using inductively coupled plasma mass spectrometry. The results showed that over the past decades, the environmental pollution was caused by a combination of Cu, Zn, Cd, and Pb, with tailings and acid mine drainage being the main pollution sources affecting soils. Significantly higher levels (P ≤ 0.05) of Cu, Zn, Cd, and Pb were found in the tailings as compared with paddy, garden, and control soils, with averages of 1 486, 2 516, 6.42, and 429 mg kg−1, respectively. These metals were continuously dispersed downstream from the tailings and waste waters, and therefore their concentrations in the paddy soils were as high as 567, 1 140, 2.48, and 191 mg kg−1, respectively, being significantly higher (P ≤ 0.05) as compared with those in the garden soils. The results of sequential extraction of the above metals from all the soil types showed that the residual fraction was the dominant form. However, the amounts of metals that were bound to Fe-Mn oxides and organic matter were relatively higher than those bound to carbonates or those that existed in exchangeable forms. As metals could be transformed from an inert state to an active state, the potential environmental risk due to these metals would increase with time.

•Surfactant-based cleanup technologies (SER, SEBR, SEPR, and SER-AOPs) are reviewed.•Drivers of different approaches in removing PAHs from soil/water are discussed.•A review on the applications of SER-based integrated technologies is given.•Toxicity of treated soil/water using the different processes should be assessed.•Scaling up the SER-based technologies is needed to assess their cost and efficacy.Surfactant-enhanced remediation (SER) is considered as a promising and efficient remediation approach. This review summarizes and discusses main drivers on the application of SER in removing polycyclic aromatic hydrocarbons (PAHs) from contaminated soil and water. The effect of PAH-PAH interactions on SER efficiency is, for the first time, illustrated in an SER review. Interactions between mixed PAHs could enhance, decrease, or have no impact on surfactants' solubilization power towards PAHs, thus affecting the optimal usage of surfactants for SER. Although SER can transfer PAHs from soil/non-aqueous phase liquids to the aqueous phase, the harmful impact of PAHs still exists. To decrease the level of PAHs in SER solutions, a series of SER-based integrated cleanup technologies have been developed including surfactant-enhanced bioremediation (SEBR), surfactant-enhanced phytoremediation (SEPR) and SER-advanced oxidation processes (SER-AOPs). In this review, the general considerations and corresponding applications of the integrated cleanup technologies are summarized and discussed. Compared with SER-AOPs, SEBR and SEPR need less operation cost, yet require more treatment time. To successfully achieve the field application of surfactant-based technologies, massive production of the cost-effective green surfactants (i.e. biosurfactants) and comprehensive evaluation of the drivers and the global cost of SER-based cleanup technologies need to be performed in the future.Download high-res image (266KB)Download full-size image