Removal Efficiency Of Surfactants Research Articles

Pontederia crassipes utilization for dual phytoremediation and adsorption in greywater treatment: a techno-economic and sustainable approach

While phytoremediation has been widely employed for greywater treatment, this system suffers from the transfer of considerable amounts of surfactants to the aquatic environment through partially treated effluent and/or exhausted plant disposal. Hence, this study focuses on greywater phytoremediation followed by recycling the spent plant for preparing an adsorbent material used as post-treatment. P. crassipes was used to operate a phytoremediation unit under 23 °C, 60% relative humidity, plant density (5–30 g/L), dilution (0–50%), pH (4–10), and retention time (3–15 days). The optimum condition was 12.7 g/L density, 34.0% dilution, pH 8.4, and 13 days, giving chemical oxygen demand (COD), surfactant, and NH4-N removal efficiencies of 94.62%, 90.45%, and 88.09%, respectively. The exhausted plant was then thermally treated at 550 °C and 40 min to obtain biochar used as adsorbent to treat the phytoremediation effluent. The optimum adsorption process was biochar dosage of 1.51 g/L, pH of 2.1, and 137 min, providing a surfactant removal efficiency of 92.56%. The final discharge of this phytoremediation/adsorption combined process contained 8.30 mg/L COD, 0.23 mg/L surfactant, and 0.94 mg/L NH4 +-N. Interestingly, this approach could be economically feasible with a payback period of 6.5 years, 14 USD net present value, and 8.6% internal rate of return.

Integrating chemical coagulation with fixed-bed column adsorption using rice husk-derived biochar for shipboard bilgewater treatment: Scale-up design and cost estimation

Discharging shipboard bilgewater (SBW) into seas and oceans without proper treatment could poison marine organisms and negatively impact transportation-related activities. This study focuses on the treatment of synthetic SBW using a simple and cost-efficient physico-chemical process. This treatment system included coagulation-flocculation (CF) using alum coagulant and fixed-bed column adsorption using rice husk-derived biochar (RHB). The optimization and effect of CF process parameters, viz., pH, fast stirring speed, and alum dosage, on surfactant and COD removal efficiencies were studied using a central composite design-response surface methodology (CCD-RSM). At optimum conditions (pH of 6.4, rapid mixing speed of 160 rpm, and coagulant dosage of 140 mg/L), the surfactants and COD removal efficiencies were 46.31±1.48% and 84.67±2.61%, respectively. The adsorption column optimum conditions were flow rate= 5 mL/min and bed depth= 16 cm, giving a surfactant removal efficiency of 96.6%. The primary adsorption mechanism was physisorption, including electrostatic attraction, hydrogen bonding, pore-filling, and hydrophobic interaction, as revealed by SEM, EDX, and FTIR characterizations. The adsorption data fitted well with Thomas model predictions, giving the best kinetic constant (KTh)= 0.305 mL/min/mg and equilibrium surfactant uptake (qo)= 11.05 mg/g (R2= 0.996). The Thomas model's coefficients were successfully used to predict the breakthrough curves and determine the column dimensions for pilot-scale (3 L/h) and large-scale (300 L/h) fixed-bed adsorption units. The estimated cost for the on-board treatment of SBW by the proposed system was 2.51 US$/m3. Future studies are required to implement the proposed combined coagulation/flocculation/adsorption system to treat real SBW from medium-sized ships.

Magnetic chitosan/calcium alginate double-network hydrogel beads: Preparation, adsorption of anionic and cationic surfactants, and reuse in the removal of methylene blue

Robust and reusable magnetic chitosan/calcium alginate double-network hydrogel beads (CSMAB) with an environmentally benign biocomposite material synthesis approach were used adsorption of surfactant and removal of methylene blue dye sequentially for the first time. Double network hydrogel structure with sodium alginate and chitosan and acidification of the surface with HCl provided the reusability of the beads at the pollutant removal in water. The CSMAB beads were characterized for structural analysis by FESEM, EDX, BET, VSM, and FTIR techniques. They were used for the adsorption of cationic hexadecylpyridinium chloride (HDPCl) and anionic sodium dodecyl sulfate (SDS) surfactants and reused in the removal of cationic methylene blue dye without any pretreatment. The effect of pH, adsorbent dose, and temperature on surfactant removal efficiency was analyzed and pH was found the statistical significance. The adsorption capacity of CSMAB beads with a surface area of 0.65 m2 g−1 was calculated as 1.9 mg g−1 for HDPCl, and 1.2 mg g−1 for SDS, respectively. The SDS and HDPCl adsorption followed the pseudo-second-order kinetic and Freundlich isotherm model. The thermodynamic results showed that the surfactant adsorption process is an exothermic and spontaneous process. SDS-reacted CSMAB beads showed higher efficiency with 61 % in the removal of methylene blue dye.

Advanced Treatment of Laundry Wastewater by Electro-Hybrid Ozonation–Coagulation Process: Surfactant and Microplastic Removal and Mechanism

Laundry wastewater is supposed to be one of the most important sources of surfactants and microplastics in the wastewater treatment plant. Consequently, the aim of the study was evaluating the performance and mechanism of the electro-hybrid ozonation–coagulation (E-HOC) process for the removal of surfactants and microplastics. In this study, the efficiency of the E-HOC process for surfactant and microplastic removal was examined at different current densities and ozone dosages. Under the optimal reaction conditions (current density 15 mA·cm−2, ozone dosage 66.2 mg·L−1), both the removal efficiency of surfactant and microplastic can reach higher than 90%. Furthermore, the mechanism of surfactant and microplastic removal was investigated by electron paramagnetic resonance (EPR) and Fourier transform infrared spectroscopy (FT-IR). The results showed that the E-HOC (carbon fiber cathode) system can produce more reactive oxygen species (ROS), which can significantly improve the removal of the contaminants. In addition, the shape, size and abundance of the microplastics were analyzed. It was found that the shape of the microplastics in laundry wastewater is mainly fiber. Microplastics less than 50 μm account for 46.9%, while only 12.4% are larger than 500 μm. The abundance of microplastics in laundry wastewater ranges between 440,000 and 1,080,000 items per 100 L. The analysis of microplastics by FT-IR showed that most of the microplastics in laundry wastewater were polyethylene, nylon and polyester. These results indicated that the E-HOC process can effectively remove surfactants and microplastics from laundry wastewater.

Duckweed Potential for the Phytoremediation of Linear Alkylbenzene Sulfonate (LAS): Identification of Some Intermediate Biodegradation Products and Evaluation of Antioxidant System.

Duckweed (Lemna minor L.) has a high potential for wastewater treatment. Here, its capability for bioremoval of linear alkylbenzene sulfonate (LAS) as one of the primary contaminants of water resources was evaluated. The effect of some operational parameters on surfactant removal efficiency was determined. Also, the impact of LAS on several physiological responses of Lemna was investigated. LAS remediation efficiency of L. minor was elevated with increasing LAS concentration, duckweed weight, and temperature. Furthermore, the optimal pH for removal was 7-8.5. The benzenesulfonate ring and five homologs of sulfophenyl carboxylate were identified as intermediates in the LAS degradation pathway. A decrease in relative growth rate and pigment contents was observed by increasing LAS concentration. In contrast, an increase in hydrogen peroxide content and electrolyte leakage indicated oxidative stress by LAS. Induction of enzymatic/non-enzymatic antioxidants was observed during the surfactant remediation process, indicating their role in overcoming free radicals generated under surfactant stress.

Surfactant removal efficiency using a multiscale flow laboratory hydrophyte system – a biodegradation experiment

Surfactant removal efficiency using a multiscale flow laboratory hydrophyte system – a biodegradation experiment

Utilization of Alyssum mucilage as a natural coagulant in oily-saline wastewater treatment

Wastewater treatment with natural coagulants is an area that is well-researched and covered in the literature, but new research in this current and ongoing field is still interesting. The present analysis was conducted as the first study to investigate the use of Alyssum mucilage as a new, natural, and cost-effective coagulant for the treatment of synthesized bilge water. To the best of the authors’ knowledge, no previous study has specifically devoted to implementing a systematic analysis of a new coagulant (Alyssum mucilage) within the framework of central composite design-response surface methodology (CCD-RSM), adaptive neuro-fuzzy inference system (ANFIS), and artificial neural network (ANN). Thus, to spot the lights over the mentioned gaps, the current study was undertaken as the first attempt to perform highly comprehensive mathematical, kinetic, and statistical analyses for a quantitative definition of the coagulation-flocculation process of oily-saline wastewater treatment using Alyssum mucilage. In this study, three process-related parameters, such as coagulant dose, contact time, and pH, were introduced for modeling, optimization, and cost analysis of the investigated application. At the optimum conditions (coagulant dose = 40.5 mg/L, pH = 7.05, and contact time = 34.9 min) of Alyssum mucilage, the maximum chemical oxygen demand (COD), turbidity (TU), and surfactant removal efficiencies were obtained as 84.63 %, 96.25 %, and 99 %, respectively. Under the optimum conditions (coagulant dose = 301.8 mg/L, pH = 6.53, and contact time = 23.1 min) of poly aluminum chloride (PAC), used as a comparative polymerized metal coagulant, the maximum COD, TU, and surfactant removal efficiencies were determined as 92.30 %, 99.92 %, and 99 %, respectively. Compared to CCD-RSM, ANFIS and ANN showed high accuracy with R2 values more than 0.990 for both PAC and Alyssum mucilage. The kinetic study revealed that the second-order model performance was superior to the first-order model. Fourier-transform infrared spectroscopy (FTIR) analysis of Alyssum mucilage demonstrated that the functional groups presented in the composition of this coagulant caused coagulation and bonding between the particles. Furthermore, the zeta potentials of bilge water, coagulant, and treated bilge water indicated that the possible mechanism of the coagulation would be adsorption and bridging.

Surfactant removal and biomass production in a microalgal-bacterial process: effect of feeding regime.

The influence of the feeding regime on surfactant and nutrient removal and biomass production was evaluated in three high rate algal ponds for primary domestic wastewater treatment. Feeding times of 24, 12 and 0.1 h d-1 were studied in each reactor at a similar hydraulic retention time of 7.0 days and organic load of 2.3 mg m-2 d-1. Semi-continuous feeding at 12 and 0.1 h d-1 showed better microalgal biomass production (0.21-0.23 g L-1) and nutrient removal, including nitrogen (74-76%) and phosphorus (80-86%), when compared to biomass production (0.13 g L-1) and nitrogen (69%) and phosphorus (46%) removals obtained at continuous feeding (24 h d-1). Additionally, the removal efficiency of surfactant in the three reactors ranged between 90 and 97%, where the best result was obtained at 0.1 h d-1, resulting in surfactant concentrations in the treated effluent (0.3 mg L-1) below the maximum freshwater discharge limits.

Phytoremediation potential of Azolla filiculoides for sodium dodecyl benzene sulfonate (SDBS) surfactant considering some physiological responses, effects of operational parameters and biodegradation of surfactant.

In this study, phytoremediation potential of the Azolla filiculoides Lam. was examined for sodium dodecyl benzene sulfonate (SDBS) anionic surfactant. Furthermore, the effect of surfactant treatment on some physiological characteristics of Azolla was studied. The surfactant bioremoval efficiency was studied under variable conditions including treatment time, initial surfactant concentration, Azolla fresh weight, temperature, and pH. Results showed that surfactant removal efficiency of A. filiculoides was significantly enhanced with increasing of temperature, initial surfactant concentration, and amount of Azolla. SDBS led to a reduction in growth rate and total chlorophyll content, but effect index of Azolla increased by higher concentrations of surfactant. In contrast, antioxidant enzymes activities including polyphenol oxidase, ascorbate peroxidase, catalase, and peroxidase, as well as nonenzymatic antioxidants such as total carotenoids and anthocyanin contents significantly increased probably due to the ability of plant to overcome oxidative stress induced by SDBS. An increase in antioxidant activity based on 2, 2-diphenyl-1-picrylhydrazil (DPPH) confirmed this fact. An increase in the amount of hydrogen peroxide and reduction in membrane stability index indicated the induction of oxidative stress. As a result of SDBS biodegradation, 6 homologs of sulfophenyl carboxylates (SPCs) including C2 to C7-SPC and benzenesulfonate ring were identified by liquid chromatography-mass spectroscopy (LC-MS) analysis.

Removal of quaternary ammonium compounds in ion exchange process

The study attempted to evaluate the effectiveness of ion exchange process in cationic surfactant (benzalkonium chloride, BAC) removal from model solutions. Four commercial cation-exchange resins were chosen for the batch tests in four doses (2.5–20 mL L-1). The experiments included evaluation of the following parameters on ion exchange efficiency: resin characteristics and dose, presence of inorganic salt and pH of treated solution. The ion exchange process was found to be very effective in cationic surfactant removal – two of tested resins allowed to remove up to 80% of contaminant after contact time of 40 minutes, the last two – after 60 minutes of mixing in all range of doses. The presence of electrolyte neither pH change has no essential effect on surfactant removal efficiency. The analysis of the ion exchange isotherms showed that the strongly-acidic macroporous resin C150 H was characterized by the highest BAC ion exchange capacity (153.8 mg mL-1), while the weakly-acidic gel resin C104 showed the best affinity of the exchanged ions to the resin matrix.

Surfactant removal with multiwalled carbon nanotubes

The ability of multiwalled carbon nanotubes (MWCNTs) to remove a non-ionic surfactant, Triton X-100 (TX100), an anionic surfactant, sodium dodecylbenzenesulonate (SDBS), and a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB) from the aqueous phase was investigated. Untreated, OH-, and COOH-functionalized MWCNTs with different outer diameters and chemical composition were examined and compared. As both the concentrations of surfactants and MWCNTs initially added may affect removal efficiency of surfactants, a relationship between the initial concentration ratio of surfactants and MWCNTs (Rc) and the removal efficiency (E) was established. The results showed that for a given Rc (e.g., 0.8), removal efficiency of the tested surfactants by a specific MWCNT (e.g., the untreated one with outer diameter <8 nm) decreased in the following order: TX100 (52.3%) > SDBS (26.2%) > CTAB (3.8%). TX100 was more readily removed by MWCNTs than SDBS and CTAB, due to its longer aliphatic chain compared to SDBS and CTAB thus higher hydrophobicity, and stronger π-π interactions with the aromatic structure of the surfaces of graphite sheets relative to CTAB. Based upon the established relationship between Rc and E of surfactants by MWCNTs, the maximum removal efficiency and the most appropriate Rc of TX100 and SDBS by two MWCNTs (UT8 and OH8) were derived. It was interesting to notice that, except for the case to remove TX100 using UT8, even though a large quantity of UT8 or OH8 was added to the TX100 or SDBS removal systems, they cannot be completely removed, with the maximum removal efficiency in the range of 55.88–87.17%. This mostly resulted from strong aggregation of MWCNTs thus reducing their readily accessible surface area and porosity for sorption.

Monitoring of Anionic Surfactants in a Wastewater Treatment Plant of Algiers Western Region by a Simplified Spectrophotometric Method

AbstractEvaluation of anionic surfactant (AS) quantities in the environment has been the subject of intensive worldwide investigation. Even so, significant questions related to their presence in Algerian wastewaters discharged into the Mediterranean Sea remain. For the first time, monitoring of AS in a wastewater treatment plant (WWTP) located about 30 km west of Algiers was carried out. Four sampling points were selected to inspect the behavior of AS and investigate surfactant removal efficiencies of the WWTP: untreated wastewaters (UW), samples clarified via primary treatment, samples biologically treated and treated waters. To achieve this work, a spectrophotometric method of AS determination has been developed. Dioctyl sulfosuccinate sodium was chosen as a reference because of its low costs and its high response, compared to other AS commonly used by this method. The effects of pH, time of extraction, and washing step were studied. The volume of solvent was optimized. The calibration curve was linear and exhibited a significant coefficient of correlation. The lower limit of detection was found to be around 10−6 M. Mechanical and biological treatments remove 53 % of AS from wastewaters before being discharged into the aquatic environment. It was found that the concentration of AS discharged into the Mediterranean Sea in the studied region reaches 10−4 M.

Microbial diversity and the implications of sulfide levels in an anaerobic reactor used to remove an anionic surfactant from laundry wastewater

The objective of this study was to evaluate the removal of linear alkylbenzene sulfonate (LAS) from commercial laundry wastewater using an expanded granular sludge bed (EGSB) reactor with two specific LAS loading rates (SLLRs), 1.0 and 2.7mgLASgVS−1d−1. The biomass was characterized using denaturing gradient gel electrophoresis (DGGE) and 16S Ion Tag sequencing. Higher LAS removal (92.9%) was observed in association with an SLLR of 1.0mgLASgVS−1d−1 than with an SLLR of 2.7mgLASgVS−1d−1 (58.6%). A relationship between the S−2 concentration in the effluent and the surfactant removal efficiency was observed. This result is indicative of the inhibition of LAS-removing microbiota at S−2 concentrations greater than 20mgSL−1. By using DGGE, microbial stratification was observed in the reactor in association with granule size, even though the reactor is considered to be a completely mixed regime. The RDP-classifier identified 175 genera, 33 of which were related to LAS degradation.

Cytotoxicity bioremoval achieved by a submerged membrane bioreactor operated at pilot scale for the treatment of surfactant wastewater

The feasibility of reclaiming an anionic surfactant-rich wastewater with a submerged membrane bioreactor was investigated in a pilot scale plant of 60 L in the frame of the FP7 BioNexGen project. The MBR was operated continuously for eight months. The effects of the HRT (from 3 to 1 d) were evaluated regarding COD and anionic surfactant removal efficiencies. At a reduced HRT of 32 h, the MBR achieved high COD and anionic surfactant removal efficiencies (83.73 and 98.13%, respectively). Considering the complexity of the wastewater processed, the MBR was very stable and achieved high organic removal efficiency at organic loading of 1.5g COD l−1 d−1 and HRT of 32 h. The evaluation of MBR potential to reduce the cytotoxicity of the investigated wastewater was studied at HRT of 32 h and OLR of 1.5g COD L−1 d−1. The toxicity bioremoval was assessed by the MTT assay on MCF-7 breast cancer cells.

Removal of the nonionic surfactant Eumulgin ES from protein solutions by means of adsorption and ultrafiltration

Aqueous micellar two-phase extraction (AMTPE) is a promising technique for large-scale protein purification, however, it is unavoidable that a certain surfactant load will remain in the product stream. Therefore, an industrial application of AMTPE requires efficient and economic ways for the removal of surfactants as a polishing step. In view of this demand, the removal of the nonionic surfactant Eumulgin ES has been investigated by means of fixed bed adsorption and cross-flow ultrafiltration. The critical micelle concentration of an aqueous Eumulgin ES solution is 9.2mg/L with a hydrodynamic diameter of a micelle of approximately 15nm at 22°C. The adsorption of Eumulgin ES to hydrophobic polystyrene beads leads to high loading capacities, but proteins also bind with high affinity to the beads, making the technique of limited use. A better way is to remove the surfactant by means of ultrafiltration through a hydrophobic polyethersulfone membrane. In the course of the filtration process a viscous micelle phase at the membrane forms, by which the flux through the membrane is decreased drastically. While elevated temperatures and salt concentrations decrease the flux and the overall separation performance, the opposite conditions lead to improved surfactant removal efficiencies. Cross-flow ultrafiltration is finally applied for the separation of Eumulgin ES from a proteinaceous solution originating from a technical-scale AMTPE investigation. The filtration results in a total surfactant removal of >98.8% from the target protein solution within 8 exchanged volumes.

Use of Surface Modified Silica gel factory Waste for Removal of 2,4-D Pesticide from Agricultural Wastewater: A case study

The silica gel waste (SGW), after its collection from a local factory (Kolkata, India) was modified with cationic surfactant and was utilized as an adsorbing media for the removal of 2,4- dichlorophenoxyacetic acid (2,4-D) from agricultural runoff of a tea garden. Characterization of base adsorbent and modified adsorbent was carried out. The efficacy of the adsorbent was evaluated through both batch and fixed bed mode. Kinetics and isotherm study were conducted and the parameters were compared with 2,4-D bearing distilled water samples. The values of diffusion coefficients were determined. Presence of electrolyte and solution pH was found to affect the performance of the adsorbent significantly. The removal efficiency of surfactant modified silica gel waste (SMSGW) in case of wastewater was found to be lower than the 2,4-D bearing distilled water sample. The data of column run was analyzed using Logit model. Batch desorption study was carried out using ethanol and acetone. The studies revealed surfactant coated SGW to be an efficient adsorbing media for 2,4-D removal.

A pilot-plant study of the adsorptive micellar flocculation process: Optimum design and operation

A pilot-plant scale study of the adsorptive micellar flocculation (AMF) process is presented for the first time, and builds on the solid foundation provided by previous fundamental laboratory studies. A number of experimental tests were conducted to validate the feasibility of using an AMF pilot rig to remove phenol from aqueous effluent streams. Several key factors, including flocculation time, floc settling time, optimum air flow-rate for agitation, and flocculant dosage, were determined. Residual concentrations in treated water indicated a surfactant removal efficiency of 95–98%, and pollutant removal reached 78% in two stages of process operation. A strategy for the separate recycling of surfactant, flocculant and pollutant has already been developed. The present study has thus made further progress in developing, testing, validating and optimising the operating conditions of a pilot-scale process. As such, it has demonstrated the feasibility of scaling up from the bench-scale to a commercial, continuously operated unit.

Dairy Waste Water Treatment by Combining Ozonation and Nanofiltration

The aim of this investigation was to examine the applicability of the membrane technique and the effect of preozonation in dairy waste water treatment technology. The best degree of surfactant removal from model anionic surfactant solution by nanofiltration was achieved at 20°C and 40 bar. Investigations on the effects of ozone treatment of the waste water indicated that preozonation decreased the flux and increased the chemical oxygen demand and surfactant removal efficiency. Ozone treatment enhanced the biodegradability of the retentate from 68.8% to 96.4%.

Removal of Organic Constituents in Municipal Sewage Using Anaerobic Fluidized Sludge Blanket and Anaerobic Filter

The removal of various organic constituents in municipal sewage was investigated using anaerobic fluidized sludge blanket. (AFSB) and anaerobic filter (AF). Experimental results revealed that the AFSB reactor could treat the sewage more efficiently than the AF reactor and the removal efficiency of organic latter greatly varied in constituents. At hydraulic retention lines in the range of 8 to 24 hours, 50% COD reduction and 59% TOC reduction can be achieved by the AFSB reactor at 37°C. Lipids, proteins and carbohydrates can be highly removed, but the removal efficiency of surfactants is very low under anaerobic conditions. Methane production was rather limied (0.12 m3/kg COD removed at STP) and the COD reioval by sulfate reduction seems not to be neglected. The sludge production during 272 day operation times was 0.272 gVSS/g COD removed in the AFSB reactor.