Optimum Removal Efficiency Research Articles

Biotransformation characteristics of tetracycline by strain Serratia marcescens MSM2304 and its mechanism evaluation based on products analysis and genomics

Microbial biotransformation is a recommended and reliable method in face of formidable tetracycline (TC) with broad-spectrum antibacterial activity. Herein, comprehensive characteristics of a newfound strain and its molecular mechanism in process of TC bioremediation were involved in this study. Specifically, Serratia marcescens MSM2304 isolated from pig manure sludge grew well in presence of TC and achieved optimal removal efficiency of 61% under conditions of initial TC concentration of 10 mg/L, pH of 7.0, cell inoculation amount of 5%, and tryptone of 10 g/L as additional carbon. The pathways of biotransformation include EPS biosorption, cell surface biosorption and biodegradation, which enzymatic processes of biodegradation were occurred through TC adsorbed by biofilms was firstly broken down by extracellular enzymes and part of TC migrated towards biofilm interior and degraded by intracellular enzymes. Wherein extracellular polysaccharides in extracellular polymeric substances (EPS) from biofilm of strain MSM2304 mainly performed extracellular adsorption, and changes in position and intensity of CO, =CH and C–O–C/C–O of EPS possible further implied TC adsorption by it. Biodegradation accounting for 79.07% played a key role in TC biotransformation and could be fitted well by first-order model that manifesting rapid and thorough removal. Potential biodegradation pathway including demethylation, dihydroxylation, oxygenation, and ring opening possibly involved in TC disposal process of MSM2304, TC-degrading metabolites exhibited lower toxicity to indicator bacteria relative to parent TC. Whole genome sequencing as underlying molecular evidence revealed that TC resistance genes, dehydrogenases-encoding genes, monooxygenase-encoding genes, and methyltransferase-encoding genes of strain MSM2304 were positively related to TC biodegradation. Collectively, these results favored a theoretical evaluation for Serratia marcescens MSM2304 as a promising TC-control agent in environmental bioremediation processes.

Deep purification of pesticide waste salt containing high-concentration organic pollutants by ethanol solvents washing and heating treatment

The increasing production of industrial waste salt has become a growing concern. These waste salts are usually filled or deposited without treatment, causing serious environmental pollution and a waste of salt resources. The ideal solution to this problem is to recycle the waste salts after the removal of organic pollutants. In this study, organic solvent washing and heating are chosen to deeply remove the organic pollutants from actual pesticide waste salts. The experimental results showed that the optimum removal efficiency of organic pollutants in waste salts achieves as high as 99.82% under the conditions of 3:5 mass-to-volume ratio of waste salts-to-ethanol (EA), heating temperature of 400 °C (60 min). In addition, the removal mechanism and migration pathways of organic pollutants in the washing and heating were proposed. Salts washing with EA could remove most of the organic pollutants and subsequent heating treatment could completely purify the waste salts without the emission of the harmful gaseous compounds. As the best eluent, EA can not only effectively remove organic pollutants, but also be readily recycled. At the same time, the EA washing and heating process could avoid the pollution of organic waste liquid and noxious tail gas. Therefore, the EA washing process has the advantages of green, high efficiency, safety and energy saving. The EA washing and heating effectively avoids the problem of environmental pollution caused by harmful gases generated by heating and promotes the purification process and reuse of industrial waste salts.

Optimal adsorption of pefloxacin antibiotics from aqueous solutions: Improved performance with metal-organic framework MIL-101(Cr)

The widespread use and subsequent release of antibiotics by humans and animals pose health and environmental risks, compelling their removal from aquatic ecosystems. MIL-101(Cr), a metal-organic framework (MOF), exhibits versatile applications in antibiotic adsorption owing to its exceptional structural characteristics. In this context, MIL-101(Cr) nanoparticles are successfully prepared via the hydrothermal method to remove pefloxacin (PEF) from aqueous solutions. The resulting MIL-101(Cr) adsorbents showcase high crystallinity (97.6%), a large surface area (3166 m2/g), broad nanopore sizes, good thermal stability, and efficient reusability. Factors including initial PEF concentration, pH, dosage of adsorbent, and temperature are thoroughly investigated. The findings reveal a good adsorption capacity (254.3 mg/g) with an optimal removal efficiency (99.7%) at 308 K in a neutral pH of 7.0 when the adsorbent dosage is 250 mg/L and the initial PEF concentration is 200 mg/L within 80 min of contact. Among the three adsorption isotherms (Langmuir, Freundlich, Temkin models), the Langmuir equation best fits the studies, indicating a maximum adsorption capacity of 253.8 mg/g at 25°C, while the experimental equilibrium adsorption capacity is 229.2 mg/g at the same temperature. Adsorption kinetics aligns with the pseudo-second-order model. Thermodynamic parameters and activation energy affirm the endothermic and spontaneous behavior of the adsorption process, attributed to both physisorption and chemisorption. This study highlights the promising potential of synthesized MOF nanocrystals as an effective adsorbent for antibiotics in wastewater treatment and environmental remediation.

Effective Removal of Carcinogenic Azo Dye from Water Using Zea mays-Derived Mesoporous Activated Carbon.

Addressing industrial wastewater treatment challenges and removing hazardous organic pollutants, such as carcinogenic methyl orange (MO) and azo dyes, is a pressing concern. This study explores the use of the Zea mays envelope, an agricultural waste product, to produce Z. mays activated carbon (ZMAC) through the chemical activation of maize envelopes with phosphoric acid. Various analytical techniques, including FTIR, XRD, TGA, DSC, and SEM, characterize ZMAC. Results show that ZMAC exhibits an impressive monolayer adsorption capacity of 66.2 mg/g for MO. The Langmuir isotherm model fits the experimental data well, indicating monolayer coverage of the MO on the ZMAC surface. The pH-sensitive adsorption process demonstrates an optimal removal efficiency at pH 4. ZMAC follows the pseudo-second-order kinetic model, and diffusion rate constant analysis identifies three consecutive stages in the adsorption process. Moreover, the uptake of MO ions by ZMAC is identified as an exothermic and spontaneous process. Reusability tests demonstrate efficient regeneration of ZMAC up to five times with 1 mL of 2 M HNO3 in each cycle, without sorbent mass loss. Thermodynamic analysis shows an increase in the uptake capacity from 66.2 to 73.2 mg/g with temperature elevation. This study offers practical solutions for industrial wastewater treatment challenges, providing an environmentally sustainable and effective approach to mitigate the risks associated with hazardous organic pollutants.

Photoreduction of atrazine from aqueous solution using sulfite/iodide/UV process, degradation, kinetics and by-products pathway

Due to its widespread use in agriculture, atrazine has entered aquatic environments and thus poses potential risks to public health. Therefore, researchers have done many studies to remove it. Advanced reduction process (ARP) is an emerging technology for degrading organic contaminants from aqueous solutions. This study was aimed at evaluating the degradation of atrazine via sulfite/iodide/UV process. The best performance (96% of atrazine degradation) was observed in the neutral pH at 60 min of reaction time, with atrazine concentration of 10 mg/L and concentration of sulfite and iodide of 1 mM. The kinetic study revealed that the removal of atrazine was matched with the pseudo-first-order model. Results have shown that reduction induced by eaq-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{e}}}_{{\ ext{aq}}}^{-}$$\\end{document} and direct photolysis dominated the degradation of atrazine. The presence of anions (Cl-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{Cl}}}^{-}$$\\end{document},CO32-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{CO}}}_{3}^{2-}$$\\end{document} and SO42-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{SO}}}_{4}^{2-}$$\\end{document}) did not have a significant effect on the degradation efficiency. In optimal conditions, COD and TOC removal efficiency were obtained at 32% and 4%, respectively. Atrazine degradation intermediates were generated by de-chlorination, hydroxylation, de-alkylation, and oxidation reactions. Overall, this research illustrated that Sulfite/iodide/UV process could be a promising approach for atrazine removal and similar contaminants from aqueous solutions.

Effects of microcystin-LR on purification efficiency of simulating drinking water source by Hydrocharis dubia (Bl.) backer

The safety of drinking water source directly affects human health. Microcystin-LR (MC-LR), a toxic and common pollutant in drinking water source, is released by algae and can impede the in-situ remediation effect of aquatic plant. Finding out the effect mechanism of MC-LR on the purification of drinking water by aquatic plant is the key to its application. This study aims to explore the performance and mechanism of MC-LR on drinking water source purification by Hydrocharis dubia (Bl.) backer. The optimum removal efficiency of NH4+-N, TP and COD were 90.7%, 93.2% and 77.3% at MC-LR concentration of 0.5 μg L−1, respectively. With the increase of MC-LR concentration, the pollutants removal rate was obviously inhibited causing by concentration-dependent. Furthermore, the growth and development of the Hydrocharis dubia (Bl.) backer roots were significantly promoted at the concentration of 0.1 μg L−1. The length, tips, surface area, and average diameter of the root increased by 71.3%, 271.4%, 265.5%, and 113.0%, respectively. Chlorophyll contents under low-concentration MC-LR show a 14.5%–15.7% promoting effect compared with the control group. The activities of POD and CAT were also stimulated with the MC-LR increasing (<1.0 μg L−1). Notably, the MDA contents increased with increasing MC-LR concentration (p < 0.01). This study indicates the effect mechanism of MC-LR on Hydrocharis dubia (Bl.) backer purification performance relies on the increased growth and enzyme activity of Hydrocharis dubia (Bl.) backer.

Evaluation of a water-based spacer fluid with additives for mud removal in well cementing operations

This research evaluates the crucial role of effective well cementing in enhancing petroleum production, with a specific emphasis on the utilization of spacer fluids for pre-cementing well cleaning. Investigating the performance of a water-based spacer fluid enriched with barite, Xanthan Gum, potato starch, and Poly-Anionic Cellulose additives, this study systematically designs and evaluates three distinct spacer fluids featuring varied additive concentrations for optimal mud removal efficiency. Notably, Spacer B1, incorporating 0.51% PAC-LV and 0.51% starch, emerges as the most successful, exhibiting an impressive 67.84% mud removal rate. The flow behavior of the spacers is aptly described by the Herschel-Buckley model, providing valuable insights into their rheological characteristics. Rigorous compatibility tests affirm the absence of fluid incompatibility, instilling confidence in the chosen spacer compositions. Introducing a 5% surfactant results in a noteworthy 7–8% average increase in mud removal from the metal cylinder wall. In summary, this study contributes valuable perspectives on optimizing both well cementing practices and spacer fluid formulations, ultimately elevating efficiency in petroleum production processes.

Intelligent algorithms-aided modeling and optimization of the deturbidization of abattoir wastewater by electrocoagulation using aluminium electrodes

The removal of turbidity from abattoir wastewater (AWW) by electrocoagulation (EC) was modeled and optimized using Artificial Intelligence (AI) algorithms. Artificial neural networks (ANN), adaptive neuro-fuzzy inference systems (ANFIS), particle swarm optimization (PSO), and genetic algorithms (GA) were the AI tools employed. Five input variables were considered: pH, current intensity, electrolysis time, settling time, and temperature. The ANN model was evaluated using the Levenberg-Marquardt (trainlm) algorithm, while the ANFIS modeling was accomplished using the Sugeno-type FIS. The ANN and ANFIS models demonstrated linear adequacy with the experimental data, with an R2 value of 0.9993 in both cases. The corresponding statistical error indices were RMSE (ANN = 5.65685E-05; ANFIS = 2.82843E-05), SSE (ANN = 1.60E-07; ANFIS = 3.4E-08), and MSE (ANN = 3.2E-09; ANFIS = 8E-10). The error indices revealed that the ANFIS model had the least performance error and is considered the most reliable of the two. The process optimization performed with GA and PSO considered turbidity removal efficiency, energy requirement, and electrode material loss. An optimal turbidity removal efficiency of 99.39 % was predicted at pH (3.1), current intensity (2 A), electrolysis time (20 min), settling time (50 min), and operating temperature (50 °C). This represents a potential for the delivery of cleaner water without the use of chemicals. The estimated power consumption and the theoretical mass of the aluminium electrode dissolved at the optimum condition were 293.33 kW h/m3 and 0.2237 g, respectively. The work successfully affirmed the effectiveness of the EC process in the removal of finely divided suspended particles from AWW and demonstrated the suitability of the AI algorithms in the modeling and optimization of the process.

Evaluating the photocatalytic performance of MOF coated on glass for degradation of gaseous styrene under visible light

Styrene is a volatile organic compound with various applications, especially in the plastics and paint industries. Exposure to it leads to symptoms such as weakness, suppression of the central nervous system, and nausea, and prolonged exposure to it increases the risk of cancer. Its removal from the air is a topic that researchers have considered. Various methods such as absorption, membrane separation, thermal and catalytic oxidation, biofiltration have been used to remove these compounds. The disadvantages of these compounds include the need for high energy, production of secondary pollutants, large space, providing environmental conditions (temperature and humidity) and long time. The photocatalyst process is considered as an advanced process due to the production of low and safe secondary pollutants. MOFs are nanoparticles with unique photocatalytic properties that convert organic pollutants into water and carbon dioxide under light irradiation and in environmental conditions, which prevent the production of secondary pollutants. The present study aimed to investigate the efficiency of MIL100 (Fe) nanoparticles coated on glass in removing styrene vapor from the air. Surface morphology, crystal structure, pore size, functional groups, and chemical composition of the catalyst were analyzed by SEM, XRD, BET, FTIR, and EDX analysis. The effect of parameters such as initial pollutant concentration, temperature, time, relative humidity, and nanoparticle concentration was evaluated as effective parameters in the removal process. Based on the results, MIL100 (Fe) 0.6 g/l with an 89% removal rate had the best performance for styrene removal. Due to its optimal removal efficiency, it can be used to degrade other air pollutants.

Investigation of cigarette effect and elastic-plastic behavior of green iron pellets on the roller screen efficiency

The green iron pellet demonstrates elastic–plastic deformation behavior during classification on a roller screen, which has a significant effect on its inefficiency due to the occurrence of phenomena such as the cigarette effect. This phenomenon causes the quantity and quality of produced pellets to drop by transferring the on-size pellets to the fine grain section and especially the oversized pellets to the product section. In this research, the effective factors in creating this phenomenon and the solutions to reduce it are investigated. It is observed that the optimum plastic behavior of the pellet and consequently the efficiency of the roller screen would be achieved when the green pellet is made from magnetite concentrate with 8 % moisture and 1 % bentonite, and roller screen operational parameters include feed rate of 1.5 t/h, the deck inclination angle of 13 degrees and the roll rotation speed of 150 rpm. The results obtained for the optimum fine removal efficiency, product screening efficiency, loss of production to undersize, on-size contamination, and oversize removal efficiency are 92.1 %, 93.7 %, 5.36 %, 5.23 %, and 73.2 %, respectively. The total screening efficiency of the roller screen is also estimated as 86.29 % and the cigarette effect is decreased to the most optimal state.

Tailoring photocatalytic performance through Fe-doped TiO2/ZnO for effective remediation of organic contaminants

The development of highly efficient photocatalysts holds significant promise for addressing contemporary environmental challenges. This study focuses on the synthesis and characterization of a novel photocatalyst, iron-doped TiO2/ZnO particles, created through the sol-gel technique. The incorporation of iron ions into the crystalline structure of TiO2/ZnO aims to enhance the photocatalytic efficiency of TiO2. The findings revealed that Fe–ZnO/TiO2 exhibits a more thermally stable lattice compared to TiO2/ZnO, thereby retarding the phase transformation from anatase to rutile under higher calcination temperature. The photocatalytic performance of the synthesized photocatalyst was evaluated through the degradation of methyl orange under visible light irradiation. A statistical response surface methodology based on a central composite design was employed to develop a predictive model for color removal (as the dependent variable) considering variations in irradiation intensity, initial color concentration, catalyst concentration, reaction time, and pH (as independent variables). The analysis of variance identified the initial color concentration as the most influential factor, negatively affecting the predicted response. The experimental values of color removal exhibited good agreement with the predicted values from the regression model with a coefficient of determination of 0.949, indicating the accuracy of this model in predicting the mentioned outcomes. The presented model indicated that, for a sample of methyl orange with an initial concentration of 21.97 ppm, a reaction time of 117.69 min under direct irradiation of 21.63 W, a catalyst concentration of 0.61 g/L, and a pH of 4.74, the optimal color removal efficiency of 78.99 % was achieved.

Construction of a new membrane bed biofilm reactor and yttria-stabilized zirconia for removing heavy metal pollutants.

The objective is to design a reactor with a composite new membrane bed biofilm reactor and yttria-stabilized zirconia. We constructed a valuable reactor using response surface methodology (RSM) for process optimization. The present system can remove heavy metal Pb from wastewater using a two-part biofilm reactor: the first reactor, which includes active sludge and media, was investigated; then, the second part, which includes membranes, was made. The amount of heavy metal removed from the effluent was measured at different pH and contact time. The results obtained from this study showed that the optimum conditions for obtaining the optimal removal efficiency separately, with a lead value of 40 mg L-1 for the MBBR reactor, had the highest removal value of 55% and for the membrane with an input lead value of 20 ppm at pH = 12 call time 30 minutes equal to 85%. All analyses in this article have been repeated numerous times to prove the repeatability.

Synthesis of Zn/Al layered double hydroxides magnetic-nanoparticle for removal of humic acid

A novel adsorbent of Zn/Al-LDH functionalized magnetic composite nanomaterial was successfully synthesis using a hydrothermal co-precipitation approach with NaOH as precipitating agent, and applied for the removal of humic acid (HA) from aqueous solution. The preparation, morphology, composition, and magnetic properties of Fe3O4 @SiO2-Zn/Al LDH were characterized by SEM, TEM, EDS, XRD, VSM, FT-IR and XPS. Batch experiments were carried out to investigate the influence of contact time, initial concentration, solution pH and conformed to the pseudo-second-order and Freundlich isotherm models. The adsorption test on HA demonstrated that Fe3O4 @SiO2-Zn/Al LDH exhibited optimal removal efficiency at pH 4.0, with an initial concentration of 100 mg/L and contact time of 10 min. At room temperature, 1 g Fe3O4 @SiO2-Zn/Al LDH demonstrated a removal capacity of 46.16 mg/g. These results indicated that lower pH were beneficial to the adsorption process. Fe3O4 coated with SiO2, which improves the stability and acid resistance of the overall material. Moreover, XRD, XPS and FT-IR analyzes proved that the electrostatic interactions and ion-exchange were responsible for removal of HA on Fe3O4 @SiO2-Zn/Al LDH.

A study on a fixed-bed for Pb(ii) removal by modified alkaline lignin-sodium alginate composite hydrogel.

In this work, alkaline lignin (AL) co-modified with trimercapto-s-triazine trisodium salt (TMT) and sodium alginate (SA) as a matrix were used to create a composite hydrogel for removing heavy metals, specifically divalent lead (Pb) from water. The obtained hydrogel beads were packed into a fixed bed, and then various operating conditions were explored to assess their impact on the efficiency of Pb(ii) removal. The findings indicated that the optimal removal efficiency for Pb(ii) was attained using an inflow rate of 0.159 L min-1, a hydrogel-II filling height of 40 cm, an initial Pb(ii) concentration of 10 mg L-1, and a bottom inflow direction. In the third adsorption-desorption cycle experiment, the breakthrough curve reached equilibrium after 650 min, in which equilibrium time for the initial breakthrough curve was 855 min, indicating that hydrogel-II exhibit good regeneration capability. This work serves as a foundation for practical applications in removing heavy metals from wastewater.

Response Surface Modelling and Optimization of Lead Adsorption from Wastewater Using Rice Husk Activated Carbon

Nigeria is renowned for its vast production of paddy rice, resulting in a significant volume of rice husk generation. Consequently, the conversion of these quantities of rice husk into beneficial applications is imperative to mitigate environmental pollution. The rice husk, procured from local millers in Zaria market, Nigeria, was subjected to thermal and chemical methods to produce activated carbon. The carbonization process involved heating at three different temperatures (300, 350 and 400 ℃) and subsequent mixing with 1M H3PO4 at a 1:2 ratio. Batch adsorption experiments were conducted, varying dosages of rice husk activated carbon (1 - 5 g), lead initial concentrations (10 - 60 mg/l), and carbonization temperatures (300 - 400 ℃). The Response Surface Methodology was utilized to model the adsorption capacities and removal efficiencies obtained. At carbonization temperature of 350 ℃, initial lead concentration of 60 mg/l, and adsorbent dosage of 3 g, the optimum removal efficiency and adsorption capacity 100% and 1.690 mg/g, respectively were observed. The veracity of the model equations was confirmed through the verification of the optimum adsorption conditions, with recorded percentage errors of 0.253% and 17.988%, for removal efficiency and adsorption capacity, respectively. The study's findings showed that rice husk activated carbon was highly effective in removing lead from wastewater. Furthermore, the model equations demonstrated reliability in forecasting the responses, and the optimum conditions were deemed valid.

UV-induced simultaneous oxidation/reduction of cefixime and chromium

This study explores a novel approach utilizing a UV-based photo-removal process to simultaneously eliminate organic (Cefixime-CFX) and inorganic (chromium) pollutants from wastewater. The photoreactor's configuration, segregating wastewater inlets and outlets, facilitates efficient removal. The study investigates the effect of various parameters such as pH, CFX:Cr molar ratio, and kinetic models on the removal efficiency.Analytical methods involve high-performance liquid chromatography for CFX concentration determination and atomic absorption for chromium measurement. Results showed that higher pH levels favored enhanced photo-removal of both compounds, with pH 9 displaying optimal removal efficiencies of 100 % for CFX and 46.7 % for chromium. The CFX/Cr molar ratio of 20:1 exhibited superior removal rates, achieving approximately 100 % CFX and 82.3 % chromium removal within 25 min. Additionally, kinetic analyses indicated the importance of pH in accelerating organic breakdown and subsequent production of reducing and oxidizing species, facilitating chromium precipitation. Effluent toxicology tests using the Kirby & Bauer method indicate a significant reduction in toxicity over time, suggesting the suitability of the effluent for discharge into the environment. Additionally, sludge analysis through FTIR identifies various chromate species produced during the photo-removal process, contributing to a comprehensive understanding of sludge composition. The investigation demonstrates that the UV-based photo-removal process efficiently removes both organic and inorganic pollutants while minimizing energy consumption and avoiding the formation of hazardous secondary intermediates. This study provides insights into a sustainable and effective method for wastewater treatment, with potential applications in environmental protection and pollution control.

Comparison of aluminum formate and traditional aluminum coagulants in structure, hydrolysates, coagulation behavior, and its corrosion resistance advantage

Aluminum formate (AF) has been considered as a superior coagulant that can decompose under the UV light without causing equipment corrosion during water treatment. The main components of the aluminum formate coagulant are aluminum formate (C3H3AlO6), aluminum formate hydrate (C3H3AlO6·3H2O), and aluminum hydrogen formate (C3H3AlO6·2H2O2). Analysis of the hydrolyzed products revealed that the content of added formic acid during the synthesis of aluminum formate is a crucial factor influencing its coagulation effectiveness. Increasing the HCOOH/Al ratio from 1.5 to 4.0 resulted in smaller mass-to-charge ratio (m/z) and higher positive charge for AF hydrolysates, with fewer undetected aluminum species present. Hydrolysates of AF 1.5 exhibited similar characteristics to those of aluminum polychloride, while AF 3.0 demonstrated optimal glucan removal efficiency (>55 %) through physical absorption rather than chemical bond bridging as the primary coagulation mechanism. The jar test results for bovine serum albumin (BSA) coagulation removal indicated a decrease in removal efficiency as the HCOOH/Al molar ratio increased from 1.5 to 4.0, accompanied by a decrease in pH conditions from 6.35 to 7.27. The highest BSA removal efficiency (58 %) was achieved using AF 1.5 at pH 6.35, suggesting that BSA molecules were captured by aluminum formate through chemical bonds such as NO-Al-, Al2(SO4)3, unlike the physical absorption effect observed in glucan coagulation process. Furthermore, it should be noted that compared to traditional aluminum salt coagulants, aluminum formate exhibits excellent pipeline corrosion resistance properties.

Aplikasi Surfaktan Alami dan Sintetis untuk Meningkatkan Penghilangan Total Petroleum Hidrokarbon dari Tanah Tercemar

Environmental pollution by petroleum hydrocarbons (total petroleum hydrocarbons) is an environmental problem affecting human health and the environment. Innovative and sustainable treatment methods are needed to solve this problem. One remediation technique that can be used is soil washing. Soil washing is a remediation technique using surfactants as a contaminant washing solution. This research study investigated the washing of soil contaminated by used motor oil using green and synthetic surfactants. The type of natural surfactant used was saponin at a concentration of 10,000 mg/L and synthetic surfactant Linear Alkylbenzene Sulfonate (LAS) at 800 mg/L. The effect of washing time and stirring speed on TPH reduction efficiency was also tested through a series of laboratory tests. Based on the statistical results, the three factors, namely surfactant type, washing time, and stirring speed, significantly influenced TPH removal. Optimum removal efficiency with LAS surfactant was obtained under washing time between 70 - 90 minutes and stirring speed between 40 - 50 rpm. Meanwhile, saponin surfactant at washing time is 60 - 80 minutes, and stirring speed is 48 - 50 rpm.

Experimental Investigation of Lanthanum-Modified Reinforced Composite Material for Phosphorus Removal

Adsorption stands as an economically viable, efficient, recyclable, operationally straightforward, cost-effective, and low-sludge method extensively employed for phosphorus removal. In an effort to enhance the adsorption capabilities of the adsorbent, this study employs the rare-earth metal lanthanum in conjunction with the group’s previously researched high-efficiency composite industrial residue phosphorus removal materials (EPRC) for modification, thereby generating lanthanum-modified reinforced composite phosphorus removal materials (La-EPRC). Subsequently, the novel material undergoes static modification, followed by experimental investigations into static and dynamic adsorption for phosphorus removal. Static adsorption experiments reveal optimal phosphorus removal efficiency when the initial phosphorus solution concentration is 20 mgP/L, with a La-EPRC particle dosage of 3 g/250 mL and a temperature of 25 °C. The removal efficiency of phosphorus particles is above 90% within the pH range of 4 to 10. Common coexisting anions in water, including Cl−, SO42−, HCO3−, and CO32−, demonstrate minimal impact on the efficacy of phosphorus removal. La-EPRC demonstrates a robust adsorption stability in both water and hot water environments. In a 2.5 mol/L NaOH solution, effective desorption of La-EPRC particles is observed, facilitating material regeneration. The raw materials for La-EPRC are easily accessible and cost-effective, imparting significant potential for widespread applications.

Remediation of 2,4-dichlorophenol-contaminated soil by electrokinetic delivery of persulfate technology.

2,4-Dichlorophenol (2,4-DCP) is difficult to degrade rapidly in the environment due to its stable chemical properties, so it was easy to lead to serious chlorophenol pollution in soil. Consequently, a remediation method which is efficient, safe, and economical is required. In this study, electrokinetic (EK) remediation was used to transfer sodium persulfate (Na2S2O8) into soil to degrade 2,4-DCP, and the effect of several factors (including the addition location of Na2S2O8, applied voltage, and running time) on the remediation efficiency was explored. The concentration of Na2S2O8, residual efficiency of 2,4-DCP and distribution characteristics of pH, and electrical conductivity were analyzed. The results showed that the cathode was the optimal position to add Na2S2O8. Under this condition, Na2S2O8 was uniformly distributed in the whole soil column through electromigration. The optimal removal efficiency of 2,4-DCP in soil by adding Na2S2O8 was approximately 26% when the voltage gradient was 1.0V/cm and the operating time was 9days, which was mainly due to the degradation of S2O82-.