Washing Solution Research Articles

Influence of Surface Groups on Electrochemical Properties of Molten Salt Synthesized Ti3C2Tx in Mild Aqueous Electrolytes

MXene, notable for its excellent electrical conductivity and tunable surface groups, has garnered widespread attention in the field of electrochemical energy storage. Here, Ti3C2Tx MXene was synthesized by a Lewis acid molten salt‐shielded synthesis (MS3). The surface groups (‐Cl, ‐O) were modified by washing Ti3C2Tx samples with various solutions (deionized water, 0.5 M hydrochloric acid (HCl), 0.5 M ammonium persulfate solution (APS)) and/or thermal treatments under an argon atmosphere at 300 °C, 500 °C, and 700 °C. It is shown that deionized water and HCl solution washing have minimal impact on the surface groups, while APS washing can increase the content of ‐O surface group. Conversely, thermal treatment may remove the ‐O. Electrochemical charge storage behavior of these Ti3C2Tx variants were further investigated in a 1 M acetate electrolyte buffered at pH=5.0. It is indicated that the ‐Cl surface group is electrochemically inert, whereas the ‐O may significantly improve the charge storage performance. Ti3C2Tx with high ‐O content delivered an impressive maximum capacity of 155 C g‐1. This research underscores the crucial role of surface groups on the electrochemical performance of Ti3C2Tx in mild aqueous electrolytes, offering valuable insights for future modifications and applications of Ti3C2Tx in energy storage technologies.

Modeling rapidly discriminative strategies of Cr contaminated soils through machine learning

Soil washing is employed to prevent the issue of Cr re-oxidation following the remediation of Cr-contaminated soil by transferring contaminants from the soil to the wash solution through the dissolving action. Nevertheless, rapidly screening effective washing agents remains challenging. This study conducted batch experiments to gather dataset on key factors (soil properties, Cr sequential extraction and type of washing agent) and Cr content after washing with 250 experimental data points. We developed 12 machine learning models, among which the light gradient boosting machine model excelled in predicting Cr content after washing, determining soil suitability for washing. Furthermore, the adaptive boosting and random forest models preferably predicted Cr content after various washing agents treatments, facilitating optimal detergent identification. Based on the feature analysis, soil pH, exchangeable potassium, reactive iron oxides, and Cr sequential extraction can account for most of the differences in washing treatment. To further validate our model, we used an additional 60 experimental data points, including soil properties with pH values beyond the range of the initial 250 data points. The R2 value of the predicted fit to the actual results was 0.801. This study provides the feasibility of improving the efficiency of technical remediation of Cr-contaminated soils.

Impact of electrolyzed water treatment on bacterial communities in food washing processes

Electrolyzed water is expected to have a sterilizing effect on bacteria and viruses, which makes it useful for hygiene management, such as cleaning dishes or medical equipment. Electrolyzed water treatment may affect the cellular structure of microbes, leading to DNA leakage or degradation. Here, we conducted a next-generation sequencing (NGS) analysis of bacterial diversity in washing solution to elucidate the impact of cleaning food surfaces with electrolyzed water. Modified primers were used to evaluate the differences between the existing primers used to obtain NGS sequences and through statistical analysis. The NGS reads obtained using the modified primers tended to reveal more Enterobacteriaceae sequences, and fewer mitochondrial sequences than did those obtained with conventional primers. An UniFrac distance analysis and Nonmetric multidimensional scaling (NMDS) revealed that the results obtained with the modified primer set made the differences between samples more distinct. Real-time polymerase chain reaction (PCR) using the template DNA obtained from an electrolyzed water or sodium hypochlorite solution wash revealed that some of the DNA could not be amplified using PCR of the 16S rRNA genes suggesting that the DNA fragmentation had occurred due to the electrolyzed water treatment. Our results revealed that the bacterial species removed from the food surfaces varied depending on the washing treatment. Electrolyzed water treatment may be advantageous for removing Enterobacteriaceae from leafy vegetables.

Quality of edible bird’s nest treated by keratinolytic enzymes-based cleaning solution

Edible bird's nest (EBN) is one of the luxury foods that is widely used as a healthy food due to its nutritional value and therapeutic benefits. The traditional EBN washing process causes a reduction in weight and nutrient content and an increase in pollutants due to the use of hydrogen peroxide. An exploratory observation method was used to examine the quality of EBN from Collocalia fuciphaga before and after washing using a washing solution based on keratinolytic enzymes. There are four stages of EBN cleaning i.e. cleaning by tap water, ethanol solution, enzyme solution at room temperature and 50oC and drying at 40oC for 42 hrs. A total of 60 EBN (unclean, n = 30) and clean, n = 30) were analyzed using the AOAC method. The mineral content of Ca, Fe, K and Mg using atomic absorption spectrophotometry (AAS) except that P was measured by spectrophotometer. A carbohydrate estimation kit was used to measure glycoprotein content and the amino acid content was determined using the HPLC method. Evaluation of the cleanliness was carried out using a scoring system by semi-trained panelists. The results obtained showed that the clean EBNs were slightly yellowish-white in color, and the cleanliness of EBN before and after cleaning increased from 2.35 to 3.84. Clean EBN protein content decreased by 7.2% while total amino acids decreased from 38.51% to 32.71%. Clean EBN contains eight essential amino acids of 17.93% with high levels of leucine, valine, arginine, and threonine (2.42-2.96%). EBN's clean ash content increased from 3.7% to 7.8%. Carbohydrate content and iron in clean EBN were 39.19±0.76% and 14.35 mg/100 g dry matter, respectively. The high levels of carbohydrates and iron appear to be good sources of glycoprotein to support health and have the potential as an alternative source of iron for people with anemia. The stepwise EBN washing method using tapwater, ethanol and a washing solution based on keratinolytic enzymes can be applied to reduce weight loss and improve the quality of EBN.

Technology for Reprocessing Mother–Wash Solution after Crystallization Purification of Spent Nuclear Fuel from High Temperature Gas-Cooled Reactor

Technology for Reprocessing Mother–Wash Solution after Crystallization Purification of Spent Nuclear Fuel from High Temperature Gas-Cooled Reactor

Simultaneously removal of PAHs from contaminated soil and effluent by integrating soil washing and advanced oxidation processes in a continuous system: Water saving, optimization and scale up modeling

Every year a large amount of clean water turns into contaminated effluent by soil washing (SW) process. The release of this effluent has become a growing environmental threat. In this study, a sustainable approach was developed for effective removal of PAHs from contaminated soil and the effluent by integrating SW and advanced oxidation processes (AOPs) in a continuous system. In the constructed continuous system, first small amount of clean water passed through the contaminated soil to remove PAHs. Then, the polluted effluent was treated by a quick AOPs and recycled for SW processes again and again until a complete removal of PHE be achieved. The performance of the continuous system was optimized and compared with batch system (no circulation) at lab scale. In addition, a scale up modeling was developed to predict the performance of continuous system at large scale. According to the results, under the optimum conditions: Tween 80 (TW80) = 6 g/L, ultrasonic = 160 kW, UV = 30 W, O3 = 5 g/h and TiO2 = 2 g/m2, the final PHE degradation efficiency of 98 % and 94 % were achieved by the continuous and batch systems after 130 and 185 min, respectively. The continuous system used 5 times less water volume than the batch system but resulted in better PAHs degradation. The scale up modeling revealed at large scale (100 kg soil), the continuous system could decrease the energy consumption and the required washing solution (water + TW80) up to 50 % and 80 %, respectively in comparison to the batch system. This work suggests a promising and practical approach for contaminated soil remediation without producing polluted water.

The potential of polyaniline-coated stationary phase in hydrophilic interaction liquid chromatography-based solid-phase extraction for glycopeptide enrichment

Glycopeptide enrichment is a crucial step in glycoproteomic analysis, often achieved through solid-phase extraction (SPE) on polar stationary phases in hydrophilic interaction liquid chromatography (HILIC). This study explores the potential of polyaniline (PANI)-coated silica gel for enriching human immunoglobulin G (IgG). Experimental conditions were varied to assess their impact on glycopeptide enrichment efficiency, comparing PANI-cotton wool SPE with conventional cotton wool as SPE sorbents. Two formic acid concentrations (0.1% and 1%) in elution solvent were tested, revealing that higher concentrations led to earlier elution of studied glycopeptides, especially for sialylated glycopeptides. Substituting formic acid with acetic acid increased the interaction of neutral glycopeptides with the PANI-modified sorbent, while sialylated glycopeptides showed no significant change in enrichment efficiency. Acetonitrile concentration in the elution solvent (5%, 10%, and 20%) affected the enrichment efficiency with most glycopeptides eluting at the lowest acetonitrile concentration. The acetonitrile concentration in conditioning and washing solutions (65%, 75%, and 85%) played a crucial role; at 65% acetonitrile, glycopeptides were least retained on the stationary phase, and neutral glycopeptides were even detected in the flow-through fraction. This study shows the potential of in-house-prepared PANI-modified sorbents for SPE-HILIC glycopeptide enrichment, highlighting the crucial role of tuning experimental conditions in sample preparation to enhance enrichment efficiency and selectivity.

Promotion of chloride removal from MSWI fly ash by an accelerated wet-carbonation process to enhance ash recycling in cement manufacture

Chlorides, sulfates, and heavy metals are the three main factors preventing the recycling of municipal solid waste incineration (MSWI) fly ash as an alternative material for cement clinker production, of which chloride plays the main role due to its extremelly hign content in fly ash. This study evaluated three wet-based pretreatment methods (water-washing, CO2-aided washing, and flue gas-aided washing) to remove chlorides using MSWI fly ashes from 13 incineration plants in China. Water washing was suitable for removing Cl- from MSWI fly ash containing a limited amount of less-soluble Cl-containing salts (Ca(OH)Cl, Ca2Al(OH)6(H2O)2Cl, and Ca6(CO3)2(OH)7Cl). However, for fly ash with a significant proportion of these less-soluble Cl-containing salts, injection of CO2/flue gas during washing promoted their decomposition and increased the chloride removal rates by 2–12%. Compared with chloride, the removal rate of sulfate was lower under all treatment scenarios and ranged from 7% to 47%. Therefore, caution should be taken when exploring techniques for the deep removal of chloride from MSWI fly ash, as sulfates may be the limiting factor in fly ash samples with low chloride contents when utilizing the fly ash for cement clinker production. Heavy metals in fly ash were not a limiting factor for any ash samples (either raw ash or treated ash) when utilizing the fly ash for clinker production. However, the dissolution of heavy metals in the washing solution deserves more attention, as a large amount of wastewater will be generated during wet-based pretreatment methods. This study confirmed that CO2/flue gas injection during washing promoted the removal of the less-soluble harmful components of fly ash, expanding the applications of ash materials.

Mechanisms of colloid removal from polydimethylsiloxane (PDMS) surfaces during washing: Implications for enhanced produce decontamination

Microbial contamination of fresh produce poses significant challenges to food safety and public health. Postharvest washing is a common practice in the fresh produce industry to reduce microbial load. This study aimed to elucidate the mechanisms involved in bacterial removal from produce surfaces during washing, using model colloids as bacterial surrogates and polydimethylsiloxane (PDMS) replicas of tomato, lettuce, and spinach as model produce surfaces. Colloids were deposited onto the PDMS surfaces and subsequently washed using different solutions (DI water, NaCl, and surfactants Tween 80 and sodium dodecyl sulfate) at varying concentrations. The PDMS surfaces were then withdrawn from the solutions at two distinct velocities. Colloid removal efficacy and the associated physicochemical interactions between colloids and substrate surfaces under various washing conditions were quantified. The results revealed that colloid removal was controlled by the residual amount of washing solution retained and contact line action. These factors, in turn, were influenced by the sample-withdrawal velocity and physicochemical properties of substrate surfaces, colloids, and washing solutions. Specifically, SDS at 2 mol/m3 combined with a slow withdrawal velocity significantly optimized colloid removal, achieving up to 79.0% efficiency. Conversely, using Tween 80 at 0.08 mol/m3 concentration significantly impeded removal efficiency. Understanding these dynamics to minimize residual solution retention and optimize colloid/bacteria movement with the contact line upon washing can significantly enhance the cleaning efficacy of fresh produce. The findings of this study provide an improved understanding on the key factors governing the retention and removal of colloidal particles (including microorganisms) that can guide the development of effective decontamination strategies.

Automated wash and reuse of disposable pipette tips in a SARS-CoV-2 RT-qPCR diagnostic pipeline

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic led to global shortages in laboratory consumables, in particular for automated PCR. The Technical University of Denmark supported Danish hospitals from 2020 to 2022, conducting SARS-CoV-2 RT-qPCR on around 10,000 patient samples daily. We encountered shortages of disposable pipette tips used with automated liquid handlers that transferred oropharyngeal swab samples to 96-well microplates before RNA extraction. To enable tip reuse, we developed an automated protocol for washing tips with a 0.5 % sodium hypochlorite solution. This effectively eliminated carry-over of genomic material and the wash solution remained effective when stored in an open reservoir at ambient temperatures for 24 h. A three-day validation setup demonstrated the robustness of the tip wash protocol. Reducing the number of tips used for transferring samples to 96-well microplates from 96 to 8 enabled us to mitigate pipette tip shortages, lower costs, and minimize plastic waste generation.

Specificity and sensitivity of an indirect fluorescent antibody test to detect antibodies against bovine viral diarrhea virus.

Since being reported in 1979 and 2006, indirect fluorescent antibody (IFA) tests have not been reported to detect bovine viral diarrhea virus (BVDV) antibodies to our knowledge. Thus, we re-evaluated the efficacy and usefulness of IFA tests for BVDV serology. We tested 4 combinations of 2 antibody conjugates (fluorescein isothiocyanate [FITC]-conjugated rabbit IgG anti-bovine IgG; rabbit IgG F(ab')2 fragment anti-bovine IgG [F(ab')2 FITC-IgG]) and 2 washing solutions (PBS; carbonate-bicarbonate-buffered saline [CBBS]) to evaluate the specificity of an IFA test for BVDV. We compared the sensitivity of the optimal combination with virus neutralization (VN) tests and an ELISA, and compared IFA with VN titers against different genotype (subgenotype) strains. For the F(ab')2 FITC-IgG/CBBS combination, only 1 of the 156 (0.6%) 4-fold diluted cattle sera resulted in a nonspecific reaction; other combinations led to a much higher incidence (22.9-37.2%). For the F(ab')2 FITC-IgG/CBBS combination, IFA detection rates were identical (36 of 59) for BVDV1 and BVDV2 genotypes, and IFA titers against them were strongly correlated (r = 0.99). The antibody-detection rates of the IFA tests were almost identical to those of VN tests and the ELISA (κ: 0.96 and 0.89, respectively). The IFA titers against 4 strains (BVDV1a, BVDV1j, BVDV2a, and an unidentified strain) were similar, 1,024 to ≥4,096, although the VN titers were different. Thus, our IFA tests were specific and sensitive, and more useful than VN tests given that the IFA tests could evaluate the immune status of cattle using a representative strain, regardless of genotype (subgenotype).

Protein-Based Rechargeable and Replaceable Antimicrobial and Antifouling Coatings on Hydrophobic Food-Contact Surfaces.

The growing concerns regarding foodborne illnesses related to fresh produce accentuate the necessity for innovative material solutions, particularly on surfaces that come into close contact with foods. This study introduces a sustainable, efficient, and removable antimicrobial and antifouling coating ideally suited for hydrophobic food-contact surfaces such as low-density polyethylene (LDPE). Developed through a crosslinking reaction involving tannic acid, gelatin, and soy protein hydrolysate, these coatings exhibit proper stability in aqueous washing solutions and effectively combat bacterial contamination and prevent biofilm formation. The unique surface architecture promotes the formation of halamine structures, enhancing antimicrobial efficacy with a rapid contact killing effect and reducing microbial contamination by up to 5 log10 cfu·cm-2 against both Escherichia coli (Gram-negative) and Listeria innocua (Gram-positive). Notably, the coatings are designed for at least five recharging cycles under mild conditions (pH6, 20 ppm free active chlorine) and can be easily removed with hot water or steam to refresh the depositions. This removal process not only conveniently aligns with existing sanitation protocols in the fresh produce industry but also facilitates the complete eradication of potential developed biofilms, outperforming uncoated LDPE coupons. Overall, these coatings represent sustainable, cost-effective, and practical advancements in food safety and are promising candidates for widespread adoption in food processing environments.

Comparative Analysis of Dilute Povidone Iodine (Betadine) versus Normal Saline in Bilateral Knee Joint Replacement Surgery: A Retrospective Cohort Study

Background: One of the proposed methods to reduce the risk of infection after joint replacement is the use of disinfectant solutions at the end of the surgery. Differing results have been reported regarding the effects of diluted povidone-iodine (betadine) washing solution and normal saline in reducing the risk of periprosthetic joint infection (PJI). The purpose of this retrospective cohort study is to compare the outcomes of diluted betadine solution with normal saline in bilateral knee replacement surgery.
 Methods: Patients who were referred to Ba’ath Hospital, Hamedan, Iran, from 2019 to 2021 for bilateral knee joint replacement were included. For each patient, one knee was washed with diluted betadine (35%), and the other with normal saline for 3 minutes before closing the wound. Demographic information, risk factors, and the rate of PJI three months after the surgery were collected and analyzed.
 Results: Out of 320 patients, 177 (55.3%) were women, and the most common underlying disease was type 2 diabetes with a frequency of 20.0%. Out of 640 operated knees, 17 cases (2.7%) of PJI occurred after surgery, of which 11 (4.3%) were washed with normal saline (P = 0.326). The multivariate regression analysis showed that being male (P = 0.028), diabetes (P = 0.030), high blood pressure (P = 0.019), and an increase in each body mass index (BMI) unit (P = 0.030) increased the chance of infection.
 Conclusion: Intraoperative irrigation with diluted betadine solution in bilateral knee replacement surgery can reduce the risk of infection, especially in patients with underlying diseases and obesity.

Effect of washing method on the reduction of insecticide residues and quality characteristics of sweet cherry fruits

Sweet cherry trees were sprayed with 5 insecticides (acetamiprid, dimethoate, lambda-cyhalothrin, malathion, tau-fluvalinate) at the recommended field doses in this study. Fruits were harvested after the pre-harvested interval for each pesticide completed and then they were immersed into tap water and three different washing solutions (with three different concentrations) for 3 minutes (at 20ºC). Insecticide concentrations were detected with a multi-residual analysis method using LC-MS/MS in Bursa Uludağ University in 2022. Following the treatments, changes in the quality characteristics of fruits were also investigated by quality (colour, texture and fruit cracking rate, water-soluble dry matter) and sensory analysis (fruit and stem colour, firmness, appearance, general acceptability). The results revealed that washing method with tap water during 3 min decreased insecticide residue level by 7-45% depending on insecticide active compound. Higher reduction rates were observed by washing with citric acid (10%), sodium bicarbonate (2.5%) and sodium hydroxide (0.5%). But significant reductions were detected only in lambda-cyhalothrin and malathion residues when compared with the newly harvested fruit samples. Processing factors (PF) of all washing methods were generally lower than 1 except for three treatments. PF values showed variations depending on the type of washing solution and the active compound of insecticides. Although washing with citric acid (10%), sodium bicarbonate (2.5%) and sodium hydroxide (0.5%) solutions caused reduction in residue levels, their negative effects on the quality and sensory characteristics of the fruits cannot be ruled out.

A closed-loop process for spent washing solution from multi-metal contaminated soil: EDTA reclamation and recycling

The proper disposal of spent soil washing solution is a great challenge to ethylenediamine tetraacetate (EDTA)-base soil washing technologies, particularly when the solution contains multi-metals. In this paper, we proposed an environmentally friendly disposal of multi-metal spent washing solution, in which the multi-metals were concentrated as hazardous precipitates for further safe disposal, and EDTA was reclaimed and recycled to further wash contaminated soil together with the cleansed process water. The results showed that Cr3+ was poorly removed by sole heavy-metal-capturing agent (HMCA) chelation because of the high solubility of HMCA-Cr, which also yielded a low percentage of EDTA reclamation in the multi-metal spent washing solution. We established a closed-loop process for the disposal of multi-metal spent washing solution by combining coagulation-flocculation-sedimentation and HMCA chelation. The novel recycling process was able to remove 99.67% Cu, 99.62% Pb, 92.48% Cd, 88.19% Sb, 84.38% As, and 82.39% Cr as precipitates from the real spent washing solution, and up to 95.64% of EDTA was reclaimed in the cleansed process water. On the average, the overall efficiency of the reclaimed EDTA solution could reach 65% of the fresh EDTA solution in extracting various HMs from contaminated soil. The recycling method provides an efficient and promising alternative for spent soil washing solution with both EDTA and process water reusage in a closed-loop process.

IgG glycopeptide enrichment using hydrophilic interaction chromatography-based solid-phase extraction on anaminopropyl column.

The sample preparation step is pivotal in glycoproteomic analysis. An effective approach in glycoprotein sample preparation involves enriching glycopeptides by solid-phase extraction (SPE) using polar stationary phases in hydrophilic interaction liquid chromatography (HILIC) mode. The aim of this work is to show how different experimental conditions influence the enrichment efficiency of glycopeptides from human immunoglobulin G (IgG) on an aminopropyl-modified SPE column. Different compositions of the elution solvent (acetonitrile, methanol, and isopropanol), along with varying concentrations of elution solvent acidifiers (formic and acetic acid), and different concentrations of acetonitrile for the conditioning and washing solvents (65%, 75%, and 85% acetonitrile) were tested to observe their effects on the glycopeptide enrichment process. Isopropanol proved less effective in enriching glycopeptides, while acetonitrile was the most efficient, with methanol in between. Higher formic acid concentrations in the elution solvent weakened the ionic interactions, particularly with sialylated glycopeptides. Substituting formic acid with acetic acid led to earlier elution of more glycopeptides. The acetonitrile concentration in conditioning and washing solutions played a key role; at 65% acetonitrile, glycopeptides were not retained on the SPE column and were detected in the flow-through fraction. Ultimately, it was proven that the enrichment method was applicable to human plasma samples, resulting in a significant decrease in the abundances of non-glycosylated peptides. To the best of our knowledge, this study represents the first systematic investigation into the impact of the mobile phase on glycopeptide enrichment using an aminopropyl-modified SPE column in HILIC mode. This study demonstrates the substantial impact of even minor variations in experimental conditions, which havenot yet beenconsidered in the literature, on SPE-HILIC glycopeptide enrichment. Consequently, meticulous optimization of these conditions is imperative to enhance the specificity and selectivity of glycoproteomic analysis, ensuring accurate and reliable quantification.

Bassmati Community: Innovating WASH and Climate Solutions in Jordan

Bassmati Community: Innovating WASH and Climate Solutions in Jordan

Comparing the impact of different adsorbed layers on the local glass transition of polymer matrices.

Chain adsorption to nanofiller interfaces creating bound layers has become central to understanding property changes in polymer nanocomposites. We determine the impact different kinds of adsorbed layers can have on the local glass transition temperature Tg of polymer matrices in a model film system using a localized fluorescence method. This work compares the adsorption and desorption of adsorbed layers grown in solution with the solution washing characteristics of adsorbed layers formed in the melt, leveraging knowledge about polymer adsorption in solution to infer the structure of adsorbed layers formed in the melt. In the limit of zero concentration after a long time in solution, we find that both kinds of adsorbed layers reach the same limiting adsorbed amount h∞(c → 0) ≈ 1 nm, appearing to evolve to the same thermodynamic equilibrium state of a near monolayer of surface coverage. We propose that melt annealing leads to a coarsening of polymer segment-surface contacts, increasing the length of trains and shrinking loops and tails, slowing the subsequent kinetics of these adsorbed chains in solution. Considering how the pyrene-labeled chains intermix with the adsorbed layer enables us to discriminate between the impact of tails, loops, and trains as threading of loops takes longer. We find that large fluffy loops, tails, and trains have little to no impact on the local Tg. A large 30K increase in local Tg is observed for 30-minsolvent washed well-annealed films at long intermixing times that we attribute to the threading of small tight loops.

Decontamination of washing solution of simulated cesium-contaminated soil by magnetic ammonium phosphomolybdate beads

Chemical extraction is an efficient and convenient method for the remediation of cesium-contaminated soils. Selective removal of cesium from washing solution also remains a challenge. The one-step extraction-adsorption method was performed to decontaminate three different land-use types of cesium-contaminated soils. The novel and magnetic adsorbent, ammonium phosphomolybdate-CoFe2O4, was successfully encapsulated in calcium alginate beads (ACCA) using the crosslinking method at room temperature for the first time. As-synthesized ACCA possesses a high and selective adsorption performance for cesium-contaminated washing solution, as well as good chemical stability and magnetic separation properties. Additionally, response surface methodology was employed to optimize the remediation process, resulting in removal rates of ACCA reaching 76%, 98%, and 95% for three simulated cesium-contaminated soils, respectively.

Application of aqueous extracts of <i>Alternanthera brasiliana, Chromolaena odorata</i> and <i>Tridax procumbens</i> plants in remediating lead contaminated soils

Soil washing is an effective method of removing lead from contaminated soils. However, great limitations abound in the choice of washing solution that is ecologically sustainable for agricultural soils. In this study, applications of plant soluble extracts in remediating of Pb contaminated soils for ecological sustainability were carried out. Batch laboratory experiments were done using aqueous extracts of Alternanthera brasiliana, Chromolaena odorata, Tridax procumbens and water as control at varying soil-pulp-densities (SPD) of 3, 6, 9, 12, 15%, and washing time of 1, 3, 6, 12 h. For contaminated soil, percentage removal efficiency followed the order: Alternanthera brasiliana (38.1±0.28%) > Chromolaena odorata (21.8±0.12%) > Tridax procumbens (21.3±0.18%). The most appropriate ratio for contaminated soil was 3% SPD at 12 h washing time. Removal efficiency was found to be substantially depended on geochemical phase of Pb (exchangeable-4.04%) in contaminated soil and washing solution pH (5.68). Lead removal efficiency was observed to increased proportionally with increasing washing time, but decreased with increasing SPD. Spike soil with high exchangeable Pb-78.9% recorded significant Pb removal of 63.4±0.24% with Alternanthera brasiliana, 47.8±0.22% with Chromolaena odorata, 38.3±0.38% with Tridax procumbens and 52.0±0.26% with water. Analysis of variance at p=0.05 indicated a significant difference inpercentage Pb removal efficiency across all the four washing solutions. However, the statistical T-test indicated no significant difference at p=0.05 in percentage Pb removal efficiency between both soils. Also, moderately positive correlations were observed between contaminated and spiked soils for Alternanthera brasiliana (0.676), Chromolaena odorata (0.570) and Tridax procumbens (0.517) while negative correlation observed for water (0.485) which served as the control. The three plant extracts exhibited good potential characteristics as washing solutions for the treatment of Pb contaminated soils. Chemical modifications are recommended to enhance and improve their efficiencies when considering the geochemical phase of Pb in soil.