Removal Percentage Research Articles

Colour and COD Removal from Food and Beverages Industrial Wastewater by using Spent Alkalis Carbide Lime (SACL)

The abundant amount of water used in the food & beverages (F&B) industry has caused the wastewater from this industry to be one of the major sources of water pollution, due to its high content of colour and chemical oxygen demand (COD). In this study, spent alkalis carbide lime (SACL) was used in treating the colour and COD simultaneously from the F&B industrial wastewater. SACL was used to reduce the amount of landfill waste and because of its similar characteristic to lime. The SACL was characterized using X-ray Diffractometer (XRD) X-ray Fluorescence (XRF), Scanning Electron Microscope (SEM), and Fourier-Transform Infrared Spectroscopy (FTIR) while the F&B industrial wastewater was characterized by using HACH DR6000 and UV-Vis Spectrophotometers. Several series of chemical precipitation experiments were conducted through jar tests to evaluate the effects of SACL dosing, pH value, and contact time on the percentage removal of colour and COD. The optimum conditions obtained from this study are pH 7 and 20 minutes, with percentage removal of 99.5% and 89.8% for colour and COD. However, the percentage removal of colour and COD decreased as contact time increased. With the same value of pH and contact time, SACL managed to remove more colours compared to lime, which is 93.6% compared to 88.54%, respectively. According to the analyses of FTIR and UV-Vis, the wastewater sample was cleaner when using SACL compared to using lime during the treatment. Thus, the study proves that SACL is a reliable alternative to treat colour and COD from F&B industrial wastewater.

VOC removal from automotive waste by supercritical CO2 extraction

This study investigated the reduction of volatile organic compounds (VOCs) from waste polypropylene (PP) from automobile bumpers by supercritical carbon dioxide (scCO2) extraction. The scCO2 extraction was performed with varying temperatures, pressures, and times in the range of 313–353 K, 10–25 MPa, and 1–6 h, respectively. At 333 K, 25 MPa, and 6 h, highly efficient removal of xylene, styrene, and total VOCs were observed, with removal percentages of >98 %. Optimal condition for VOC removal using scCO2 based on response surface methodology was determined to be 313 K, 10 MPa, and 2.17 h. No differences in size and color were observed in the scCO2-treated PP pellets. Moreover, VOC removal using scCO2 did not induce noticeable changes in the chemical and thermal properties of the treated PP samples. This result demonstrated that scCO2 extraction is a promising method for the VOC removal from automobile plastic waste.

Comparison of the natural and surfactant-modified zeolites in the adsorption efficiency of sunset yellow food dye from aqueous solutions

The removal of Sunset Yellow (E110) on natural zeolite and zeolite modified with the cationic surfactant cetyl pyridinium chloride (CPC) was studied using the adsorption method. The structural characteristics of the surfactant-modified zeolite (SMZ-CPC) were investigated using X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis, and the scanning electron microscopy (SEM) images. The effect of different parameters on the adsorption process, such as equilibration time and amount of adsorbent at 298 K, were determined using UV–Vis spectroscopy. The maximum dye removal percentage on SMZ-CPC was obtained with 0.08 g of adsorbent in 30 min. The results show that the zeolite modified with CPC surfactant (SMZ) has a higher adsorption capacity for Sunset Yellow than the unmodified zeolite (natural form). The experimental adsorption data were nonlinearly analyzed using isotherm equations such as Langmuir, Freundlich, Temkin, Langmuir-Freundlich (or Sips), and Extended Langmuir (EL). The experimental data were better fitted with the Sips isotherm. The adsorption kinetic data were analyzed using eight models in nonlinear forms: the pseudo-first-order (PFO), pseudo-second-order (PSO), integrated kinetic Langmuir (IKL), Elovich, intraparticle diffusion (IPD), mixed order rate equation (MOE), fractal-like pseudo-first-order (FL-PFO) and fractal-like pseudo-second-order (FL-PSO). According to the results of the coefficient of determination (R2), Elovich kinetic model well expressed E110 adsorption onto SMZ-CPC. Most of the dye removal takes place in less than 5 min and the maximum adsorption capacity is 5.06 mg/g. The results of this study show that zeolite modified with cationic surfactant is an effective adsorbent for removal anionic dyes from an aqueous solution.

Evaluation of Empty Fava Beans Pods as Bioadsorbent for the Removal of Pb2+ from Aqueous Solutions Using Phytoadsorption Technique

Environmental contamination with toxic heavy metals is a globally concerned issue. Cleaning up heavy metals from contaminated aquatic systems forces a lot of challenges. Phytoremediation processes are the interesting safe techniques that were focused by scientists and governments during the last decades for the up-taking of toxic heavy metals from ecosystems. Consequently, phytoadsorption approach was applied in this research using dry empty pods of fava beans (Vicia faba L.) to evaluate their potential for the removal of toxic lead heavy metal from its aqueous solutions. We have developed a green and simple method to remove lead ions (Pb2+) from their aquatic system. The obtained results have showed that the 350‒1000-μm biomass particles of fava beans pods were able to take up lead ions at highly rated removal percentages and high adsorption capacity using 100-ml, 100-ppm solutions at room temperature and neutral pH. For example, the highest removal percentage of lead ions was 66.8% with an absorption capacity of 3.34 mg/g using 2.0 g at a shaking rate of 200 OSC/min after 30 min. On the other hand, the removal percentage of lead ions using 0.1 g of fava beans pods biomass was 36.8 % with the highest absorption capacity of 36.8 mg/g at a shaking rate of 800 OSC/min at the same period of time. Therefore, the empty fava beans (Vicia faba L.) pods can be used as potential phytoadsorbents for the removal of lead and other heavy metals from the contaminated aquatic ecosystems.

An Investigation of Lanthanum Recovery from an Aqueous Solution by Adsorption (Ion Exchange)

Lanthanum (La(III)) is one of the high-demand rare earth elements with applications in various products. However, La(III) in mining waste streams and electronic waste also poses environmental and health concerns. Therefore, the recovery of La(III) in the waste is needed. In the present study, the adsorption of La(III) with Dowex 50W-X8, Amberchrom50WX4, Amberlyst 15, and Amberchrom 50WX2 was evaluated using a shaker water bath. Dowex 50W-X8 was found to be the best adsorbent and was used to investigate the effect of the shaker speed (RPM = 50–150), adsorbent dosage (1.0–4.0 g), pH (2.0–7.0), and temperature (20–40 °C) on adsorption. La(III) adsorption was found to increase with the shaker speed, as expected. On the other hand, the adsorption capacity decreased with the adsorbent amount. Also, the highest La(III) adsorption was observed at pH = 6.0. La(III) percentage removal did not vary significantly with a temperature from 20 °C to 40 °C. However, the first-order kinetic rate constant decreased moderately with increases in temperature. The adsorption of La(III) by Dowex 50-X8 followed the Freundlich isotherm model better than the Langmuir model. In addition, the adsorption kinetics were represented well by the pseudo-first-order kinetic model. Moreover, enthalpy and Gibbs free energy changes were found to be negative, indicating an exothermic and thermodynamically favorable adsorption process.

Microalgae-fungal pellets as novel dual-bioadsorbents for dye and their practical applications in bioremediation of palm oil mill effluent

Microalgae-fungal pellets were applied as novel dual-biosorbents for dye removal compared to fungal pellets. Both pellet types effectively removed anionic dyes better than cationic dyes, with the maximum adsorbing efficiency being nearly 100 % at a wide pH range of 3–8. The adsorption isotherms of anionic Congo Red dye and Coomassie brilliant blue R-250 dye using both pellet types and their biosorption kinetics were intensively studied. Noteworthy, the maximum adsorption capacity and affinity of microalgae-fungal pellets were much higher than those of fungal pellets. Both fungal pellets were also applied in the bioremediation of palm oil mill effluent (POME). The repeated treatment of POME by replacing pellets every 12 h enhanced the percent removal of color, phenolic compounds, and COD up to 90.97 ± 0.36 %, 70.71 ± 0.90 % and 56.55 ± 1.98 %, respectively. This study has demonstrated the promising potential for addressing dye removal and bioremediation of colored-industrial effluent in a sustainable and economically viable manner.

Development of two-dimensional amyloid fibril/carboxymethyl cellulose hybrid membranes for effective adsorption of hexavalent chromium

Amyloid fibrils (AFs) are protein aggregates with highly ordered fibrillar structures and can be formed via self-assembly of proteins under appropriate conditions. Owing to the unique properties of AFs, e.g., high surface-to-volume ratio and versatile functional groups, they offer abundant binding sites for the efficient adsorption of hexavalent chromium (Cr(VI)). This study was aimed at examining the performance of two-dimensional AF-based hybrid membranes for adsorbing Cr(VI). First, AF/carboxymethyl cellulose (AF/CMC) hybrid membranes were synthesized via chemical crosslinking coupled with phase inversion, followed by investigating the synthesis mechanism using Fourier transform infrared spectroscopy. Our results revealed that the surface microstructures and mechanical properties of the hybrid membranes could be affected by the AF:CMC mass ratio of the membrane. The porosity and ζ-potential of hybrid membranes were found to be dependent on both pH value and membrane composition. Analyses of the kinetics and thermodynamic behavior of Cr(VI) adsorption on the AF/CMC hybrid membranes revealed that the initial adsorption rate and maximum adsorption capacity were determined to be ∼149.20 mg g–1 h–1 and ∼311.11 mg g–1, respectively. The Cr(VI) removal percentage of hybrid membrane with high CMC content was found to remain at >75 % after five successive adsorption-desorption cycles. Finally, the mechanism and interactions involved in the adsorption of Cr(VI) on the hybrid membrane were further investigated via thermodynamic analysis and X-ray photoelectron spectroscopy. This study provides an excellent example of harnessing AF-based membranes in water remediation, highlighting the potential of AF-based hybrid materials for wastewater treatment applications.

Efficiency of water hyacinth and cattail for wastewater treatment using constructed wetland

Constructed wetlands have emerged as a cost-effective, eco- friendly and sustainable solution to enhance water quality by effectively removing nutrients. The objective of this study is to compare water hyacinth (Eichhornia crassipes) and Cattail (Typha latifolia) as wetland plants for wastewater treatment at the National Water Resources Institute (NWRI) situated in Kaduna State, Nigeria. The percentage removal of various parameters including pH, Total Dissolved Solids (TDS), Turbidity, Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Phosphorus, Nitrate, Ammonia, Sulphate, Oil and Grease, Total Coliform, Feacal Coliform, Copper, Zinc, Iron and Lead were compared for cattail and water hyacinth. The results of the analyzed parameters were compared with the Food and Agricultural Organization of United Nations (FAO, 2015) limits for irrigation purposes. Results showed pH, TDS, Turbidity, TSS, Sulphate, Nitrate, BOD, COD, FC, and Iron, Copper, Lead and Zinc were within permissible limit of the standard for irrigation water quality according to FAO, while EC and Total Phosphorous were above the maximum permissible limit. The result of the percentage removal efficiency showed that water hyacinth had higher performance in removing the pH (13.34%), Turbidity (97.24%), Sulphate (100%), Nitrate (18.51%), Total Phosphorous (96.34%), COD (86.21%), BOD (77.92%), Oil and Grease (73.80%), FC (78.48%), TC (36.24%), Copper (81.84%), Lead (89.69%) and Zinc (79.38%) compared to typha latifolia. For 82.61% EC, 82.09% TDS, 94.51% TSS, 97.31% Iron and removal, efficiency of typha latifolia was higher. Constructed Wetland vegetated with typha latifolia and Eichhornia crassipes showed high contaminant removal efficiency with water hyacinth showing superior removal efficiency

Green Synthesis of Metal Nanoparticles with Borojó (Borojoa patinoi) Extracts and Their Application in As Removal in Water Matrix.

The predominant aim of the current research was to generate a proposal for the removal of arsenic, a highly toxic pollutant, encountered within the Papallacta Lagoon in Ecuador. The average concentrations of As yielded ranges between 18 to 652 μg/L, through the use of metallic nanoparticles. Sampling was performed in the lagoon with their respective geographic locations and "in situ" parameters. Nanoparticles of Mn3O4 NPs, Fe3O4 NPs, and CuO NPs were synthesized at a 0.5 M concentration, using the precipitation method, and borojó (Borojoa patinoi) extract was added as an anti-caking agent as well as antioxidant. The nanoparticles were characterized by visible spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. After arsenic removal treatment using nanoparticles, a randomized experimental design of different concentrations (5 mg/L, 10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, and 150 mg/L) was applied at laboratory level. The average diameter of Fe3O4NPs ranged from 9 nm to 36 nm, Mn3O4 NPs were 15-20 nm, and CuO NPs ranged from 25 nm to 30 nm. Arsenic removal percentages using Fe3O4 NPs with a concentration of 150 mg/L was 87%; with Mn3O4 NPs, the removal was 70% and CuO NPs of about 63.5%. Finally, these nanoparticles could be used in a water treatment plant for the Papallacta Lagoon.

Surface-coated PVDF@TAPEG selective ultrafiltration membranes: an investigation on membranes’ hydrophilicity, and antifouling characteristics for effective humic acid removal from wastewater

This research aimed to synthesize polyvinyl fluoride membranes and coat them with tannic acid (TA) nanoparticles and polyethylene glycol (PEG) additives so that the membrane’s removal efficacy for humic acid (HA) pollutant from agricultural wastewater was investigated. Thus, six membranes with PEG:TA ratios of 0:0, 1:0, 0:1, 1:1, 4:1, and 1:4 were synthesized. Then, the membranes’ characteristics were identified by FTIR-ATR, FESEM, and AFM analysis, and HA’s particle size and zeta potential were also investigated. Based on optimizing effective parameters, the operating pressure of 1.5 bar and HA concentration of 80 ppm were selected as optimal values. The membrane with PEG:TA = 4:1, as the optimally modified membrane, had a pure water flux of 446.03 L/m2.h, effluent flux of 72.43 L/m2.h, and pollutant removal rate of 86.62% at pH = 7 after 60 min had passed. These values for the pristine membrane (PEG:TA = 0:0) were 265.64 L/m2.h, 89.39 L/m2.h, and 75.59%, respectively. The results showed that although the effluent flux was lower in the optimized modified membrane than in the pristine membrane, HA removal percentage was increased.

DFT theoretical analysis, experimental approach, and RSM process to understand the congo red adsorption mechanism on Chitosan@Graphene oxide beads

The presence of Congo red in wastewater poses significant environmental and health risks due to its toxic and carcinogenic properties. As a synthetic azo dye commonly used in the textile industry, Congo red is resistant to degradation, leading to persistent contamination in water bodies. The study focused on evaluating the efficacy of novel composite beads made from chitosan and graphene oxide as adsorbents for eliminating Congo Red from water solutions. It systematically examined various experimental factors including initial concentration, pH levels, mass of adsorbent, contact duration, and temperature, aiming to optimize the adsorption process. The composite chitosan graphene oxide beads were analyzed using several techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) method for specific surface area determination. The study involved extracting chitosan from shrimp shells and synthesizing graphene oxide from graphite using the Hummers method to enhance Congo Red adsorption efficiency. Comprehensive analysis of the composite beads assessed their physical and functional properties using various techniques. X-ray diffraction and infrared analysis identified their adsorption capabilities, while SEM and BET analysis characterized the porous surface structure of the beads. Maximum adsorption efficiency of 169.49 mg/g was achieved with an adsorbent mass of 0.05 g at pH 3. Kinetic, isotherm, and thermodynamic studies indicated an endothermic process following pseudo-second-order kinetics and the Langmuir isotherm model. The high regression coefficient R 2=0.9953 indicates the strong validity of employing Response Surface Methodology combined with the Box-Behnken Design (RSM-BBD) for accurately predicting the percentage of CR removal through adsorption. Theoretical Density Functional Theory (DFT) analysis elucidated interactions between Congo Red and the reactive sites within the chitosan/graphene oxide beads, providing insights into the adsorption mechanism.

Central composite experimental design for Indigo Carmine dye removal from solutions by applying electro-coagulation and electro-oxidation processes

Textile and food industries produce toxic or harmfull dye-containing wastewaters that should be treated for safely discharge. The electro-coagulation (EC) and the electro-oxidation (EO) methods for removal of dyes from wastewaters are being investigated nowadays by researchers. In this study, the Indigo Carmine, a textile and food coloring agent, removal was investigated by applying the electro-coagulation and the electro-oxidation methods. For this purpose, aluminum electrodes for EC and graphite plates for EO were used. The central composite experimental design was applied as the optimization method for the EC and the EO processes. The optimization parameters were selected as time (10-30 minutes), current density (0.4-2 Ampere/500 mL) and concentration (50-250 mg/L), natural pH (5.78-6.90) and room temperature (20-25 °C). The EO process was determined to be effective than the EC process. Statistically important parameters were concentration and time-current density interaction for the EC, but all the parameters were statistically unimportant for the EO. Dye removal percentages by the EC were calculated between 82.75% and 98.38%, and dye removal percentages by the EO were calculated between 46.88% and 100% for the determined experimental matrix. Electrical consumptions were almost equal for the EO and the EO prosesses. A column ion exchange process (Selion SBA 2000 resin) was applied to the dye residue after the EO treatment. From the oxidation reduction measurements, the treated solutions were determined as dischargeable.

Integrated treatment of black wastewater using sedimentation, constructed wetland, and nanoparticles coagulation

ABSTRACT The aim of the present investigation was to achieve an efficient treatment for black wastewater for non-restricted reuse. The treatment included sedimentation followed by horizontal flow constructed wetland (HF-CW), and finally chemical coagulation using magnetite (Fe3O4) nanoparticles. For the wetland, the average organic loading rate (OLR) was 42.83 biochemical oxygen demand (BOD)/m2day and 71.30 g chemical oxygen demand (COD)/m2 day, while average surface loading rate was 0.185 m3/m2 day. The obtained results revealed that removal percentage of COD, BOD, and total suspended solids (TSS) by sedimentation followed by processing through wetlands was 80.3, 81.6, and 80%, which corresponds to 76, 42.56, and 54 mg/l, respectively. When magnetite nanoparticles were added to the HF-CW effluent at the optimum dose of 25 mg/l in combination with 10 mg/l FeCl3, the overall removal rate increased to reach 95.9, 99.1, 99.17, 92.3, 94.3, 94.3, and 91.3% for turbidity, COD, BOD, TSS, phosphate (PO4), total nitrogen (TN), and sulfide, respectively. The corresponding residual concentrations were 5 NTU, 8, 5, 18 according to table 3, 0.07, 1, and 1.04 mg/l, respectively. According to the national and international regulations, the present final treated effluent can be safely reused as a non-restricted source for agriculture purposes. The overall results revealed that the implemented study is simple, efficient, reliable, and economical, particularly for remote areas, according to the non-restricted reuse requirements.

Effective remediation of mercury (II) from aqueous solutions using CS-MnFe2O4-CoS-MWCNTs: Box-Behnken design optimization and adsorption isotherm, kinetics, and thermodynamics evaluation.

Mercury (Hg) is a hazardous heavy metal, non-biodegradable and toxic, posing a serious threat to aquatic life and human health. Therefore, the removal of Hg ions from contaminated water using effective and eco-friendly adsorbents is necessary. In the present study, three magnetic chitosan-based organic-inorganic nanocomposites, such as CS-MnFe2O4, CS-MnFe2O4-CoS, and CS-MnFe2O4-CoS-MWCNTs, were designed and constructed to investigate their capacity for adsorbing Hg ions from aqueous solutions. The physicochemical properties of prepared composites were characterized by various analyses. The BET analyses indicated their high surface area and porous structure, and the N2 adsorption-desorption showed that the modification of CS in three stages by MnFe2O4 and crosslinking reaction, CoS preparation, and MWCNT incorporation resulted in increased N2 adsorption. The XRD confirms the synthesis of MnFe2O4 and CoS in the CS matrix and also the distinct peaks of MWCNTs. The CS-MnFe2O4-CoS-MWCNTs showed acceptable thermal stability with 45% char yields and superparamagnetic properties with magnetic saturation (Ms) of 16 emu g-1. The interactive impacts of independent variables (pH, contact time, and adsorbent dosage) on the removal percentage of Hg(II) onto three prepared adsorbents, as well as the process optimization, were assessed by the Box-Behnken design. The optimum conditions were identified, and the data from the analysis of variance showed that the three independent factors (pH, contact time, and adsorbent dosage) significantly influenced the adsorption of Hg(II). The adsorption isotherm and thermodynamics analysis investigation showed that at low concentrations of Hg(II), the adsorption process was both endothermic and spontaneous for the studied adsorbents.

Adsorptive removal of naproxen onto nano magnesium oxide-modified castor wood biochar: Treatment of pharmaceutical wastewater via sequential Fenton's-adsorption process.

This current investigation explored the thermal conversion process of castor wood into biochar, which was subsequently harnessed for removing naproxen from pharmaceutical industrial effluent via adsorption. Surface composition analyses conducted through scanning electron microscopy-energy dispersive X-ray, laser-induced breakdown spectroscopy, and Fourier-transform infrared studies unveiled the presence of nano MgO particles within the adsorbent material. Employing optimization techniques such as response surface methodology facilitated a refined approach to batch study. The optimized conditions for batch naproxen sodium (NPX) adsorption on nano-MgO-modified biochar were identified as pH 4, 1.5 g/L adsorbent dosage, and a 120-min contact time maintaining a constant NPX concentration of 10 mg/L. The adsorption capacity was calculated to be 123.34 mg/g for a nano-magnesium oxide-modified castor wood biochar (modified biochar) and 99.874 mg/g for pristine castor wood biochar (pristine biochar). Fenton's reagents comprising 15 mM of FeSO4 (7H2O) and 25 mM of H2O2 have been scrutinized under conditions of pH 3.0, a reaction time of 30 min, a temperature of 30°C, and stirring at 120 rpm, followed by batch adsorption treatment. The COD, NH3-N, NO3 -, PO4 3-, and NPX removal percentages was found to be 90%, 87%, 79%, 80%, and 90%, respectively. Thus nano MgO-modified biochar holds promise of treatment of pharmaceutical effluent.

P-32 powdered activated carbon detoxifies potentially toxic elements in the Kumasi Abattoir Ghana effluent

Industrial activities, particularly from abattoirs without effluent treatment facilities, threaten ecosystems, releasing a spectrum of potentially toxic elements (PTEs) into the environment. With a defunct wastewater treatment plant (WTP), exploring a low-cost but efficacious and eco-friendly adsorbent for the Kumasi Abattoir Ghana (KAG) effluent treatment is warranted. The study is the first attempt to utilize activated carbon (AC), such as the P-32 Powdered AC (PAC) brand, to detoxify PTEs—Cadmium (Cd), Copper (Cu), Zinc (Zn), Iron (Fe), and Lead (Pb)—in Ghana’s abattoir effluent. The adsorbent was manufactured and supplied by the Climate/Environmental Research and Technology (CLERET) Laboratory, one of the Research and Development (R&D) departments of Explore Scientific Innovations (ESI) Ltd., Ghana, using palm nutshell wastes as precursor. The study systematically evaluated the efficiency and adsorption prowess using incremental masses of 0.5, 1.0, 1.5, 2.0, and 2.5 g of the adsorbent/100 ml effluent, with three replicates per experimental unit in one cycle application of the adsorbent. The PTE concentrations were determined using standard methods before and after applying the adsorbent. Three adsorption isotherm models Langmuir, Freundlich, and Elovich, were applied to investigate the adsorption mechanisms governing the PTEs. The model performance was evaluated using R2 and Root Mean Squared Error (RMSE) metrics. The findings unveiled varied percentage removal efficiencies (% Rs), with Zn exhibiting the highest (79.64 %) at 2.5 g and Cd the least (7.8 %) at 0.5 g, of the carbon. The Freundlich isotherm emerged as the most robust model, consistently exhibiting the highest coefficient of determination (R2) with the lowest RSME values. Fe and Cd had the highest and lowest adsorption capacity (Kf) of 0.181 and 0.001, respectively. The Freundlich exponent (nf) values were within the favorability range of 1–10. The PTE adsorptions were physical rather than chemical. P-32 PAC provided a promising avenue for abattoir effluent management.

Examining the efficacy of biological filters in the removal of agricultural pesticides and nutrient elements from agricultural drainage water

The high water consumption in agriculture has led to an obvious water crisis in this sector, and the use of unconventional water sources, especially agricultural drains, is considered necessary. For this purpose, the present study was carried out to evaluate the efficiency of biological filters with different types of substrates for treating agricultural wastewater in Khuzestan province, located in the south of Iran, to use receptive resources and reuse them in agriculture. Next, the efficiency of four types of biological filters for treating agricultural drainage water with different retention times was evaluated. Sawdust, cotton stalks, wheat straw, stubble, and rice husk were used as filters. Qualitative factors included agricultural pesticides (Atrazine, Randup, Paraquat, and 2, 4-D) and nutrients (nitrate, nitrogen, phosphate, and phosphorus). By examining the trend of increasing the retention time and the corresponding removal percentage, it was observed that the retention time has a direct relationship with the amount of removal efficiency of nutrients and agricultural toxins. As the residence time increases, the average amount of nutrient compounds in different filters decreases, and their removal percentage increases. The highest removal percentage of nitrate, total nitrogen, phosphate, and total phosphorus was 74.03, 71.66, 57.97, and 61.85% in the sawdust filter and was assigned to 10 days. The highest percentage of removal of Atrazine, Tofudi, Paraquat, and Roundup toxins with a removal efficiency of 91.73, 84.27, 89.81, and 88.46% was also observed in the treatment of sawdust for 10 days. The sawdust filter showed a good performance in removing the parameters of agricultural toxins and nutrient compounds in a retention time of 10 days compared to other filters and retention times. As a general result, the sawdust filter can be cited as a reliable substrate with acceptable efficiency compared to other filters.

Voltage-confined flow-through anodic oxidation enables efficient pollutant removal and no chlorinated byproducts formation

The formation of chlorinated by-products in the treatment of chloride-laden water/wastewater by advanced oxidation processes (AOPs) has become a severe challenge to their environmentally benign application. Herein, we propose an efficient and safe alternative, i.e., flow-through anodic oxidation (FTAO) system based on the nonradical direct electron transfer (DET) process at low voltage. By controlling the anode potential below the threshold for chlorine evolution at the anode, this system achieved zero formation of inorganic and organic chlorinated byproducts whilst significantly eliminated the biotoxicity of the parent micropollutant. Meanwhile, due to the nonradical direct oxidation mechanism, the voltage-confined FTAO system attained high efficiency and selectivity for the micropollutant removal from a complex matrix containing naturally co-existing anions and organic matter. The feasibility of FTAO applications was further evaluated by removing various pollutants (including antibiotics and phenols) from actual municipal effluent and surface water. More than 96% percentage removal was achieved at extremely low energy consumption (0.003–0.017 kWh m−3). In summary, our results provide insight into the development of novel electrochemical technologies free from secondary pollution towards environmental remediation applications and beyond.

Assessment of selenium-enriched deactivated probiotic yeast efficiency in patulin detoxification in apple juice

Patulin (PAT) contamination in fruits, particularly apples and their products, poses a significant health hazard. This research aimed to eliminate PAT from simulated juice solution and actual apple juice using live and ultrasonically deactivated (D) probiotic yeasts, specifically Saccharomyces cerevisiae (S.c) and Saccharomyces boulardii (S.b) yeasts enriched with selenium (Se). The Se-enriched yeasts were analyzed using various techniques including Fourier transform infrared spectrometer (FT-IR), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), and Inductively coupled plasma–optical emission spectroscopy (ICP-OES). The study assessed the effects of yeast type, contact time (2–18 h), ultrasound treatment, and initial concentration of PAT (50–150 μg.L−1) on PAT adsorption. The most effective treatment involved the Se-S.b-D yeast strain, with an initial PAT concentration of 50 μg.L−1 for 10 h, exhibiting notable toxin removal percentages in both the apple juice simulator (98.27% reduction equivalent to 49.135 μg.L−1) and real apple juice (87.19%). The detoxification outcomes were consistent with pseudo-second-order kinetic and Langmuir isotherm models, indicating that Se-S.b-D is a biocompatible and low-cost strain with high efficiency to remove PAT in aqueous solutions.

The fate of sulfamethoxazole in microcosms of the macrophyte Schoenoplectus californicus and its impact on microbial communities

Sulfamethoxazole is a widely used antibiotic frequently found as an environmental pollutant. It can alter microbial communities and increase antibiotic resistance, becoming a public health risk. Constructed wetlands have the potential for removing sulfamethoxazole from polluted waters, but the role of different macrophytes in this process is not well understood. We investigated the fate of sulfamethoxazole and its effect on bacterial communities in microcosms containing Schoenoplectus californicus, an altitude-tolerant macrophyte. Within the first 10 h after introducing sulfamethoxazole (initial concentration 5 mg/L) to the microcosms, the concentration in the liquid phase significantly differed between microcosms with and without S. californicus. However, over the long term (15 and 30 days post-addition), the removal percentage (around 75%) in the liquid phase was not significantly influenced by S. californicus, indicating that sediments might be primarily responsible for removing the antibiotic. The presence of S. californicus promoted algae growth in the microcosms, and we determined that algae contributed to sulfamethoxazole removal from the liquid phase, likely through adsorption. Additionally, we characterized bacterial communities in the microcosm sediments via nanopore sequencing to identify changes following sulfamethoxazole addition. The relative abundance of Proteobacteria increased from 37-46% to 48–99% with the addition of the antibiotic. Conversely, the relative abundance of cyanobacteria decreased significantly after sulfamethoxazole was added (from 17 to 35% to less than 2%), suggesting it may serve as a biological marker for sulfamethoxazole pollution. In addition, the functional profile of the community was estimated from taxonomic diversity using PICRUST.