Washing Conditions Research Articles

Water, Sanitation, and Hygiene in Parts of Lagos Metropolis

The study examined water, sanitation, and hygiene conditions in Lagos State University, Yaba College ofTechnology, and Adeniran Ogunsanya College of Education tertiary institutions in parts of the Lagos metropolisusing field observation and social survey. A total of 220 structured questionnaires were administered to studentsand staff across the institutions using a random sampling technique. Descriptive statistics and ANOVA wasemployed to analyse the data. The result shows that approximately 54% of the respondents are acquainted withthe WaSH program. The significant water supply sources include borehole and public piped borne waterrepresenting 86 and 13%, respectively. About 96, 94, 91 and 37% of the respondents gained access to wastebins, sanitation, water, and handwashing materials. The ANOVA shows a significant difference between thedependent variables across the institutions. At the same time, the post-hoc tests confirm a significant differencebetween YABATECH and the other two institutions at p< 0.05 level of significance. The study provides baselineinformation on WaSH conditions for effective planning and managing WaSH facilities by policymakers inNigerian public tertiary institutions. The study concluded that safe water supply and access to handwashingfacilities is low in the area. YABATECH has the worst WaSH condition. We recommended investment in WaSHservices in tertiary institutions with greater priority at YABATECH, considering its poor WaSH amenities.

Naturally occurring dipeptide from elite controllers with dual anti-HIV-1 mechanism

BackgroundEnhanced levels of a dipeptide, WG-am, have been reported among elite controllers – patients who spontaneously control their HIV-1 infection. This study aimed to evaluate anti-HIV-1 activity and mechanism of action of WG-am. MethodsDrug sensitivity assays in TZM.bl cells, PBMCs and ACH-2 cells using WT and mutated HIV-1 strainswere performed to evaluate the antiviral mechanism of WG-am. Mass spectrometry-based proteomics and Real-time PCR analysis of reverse transcription steps were performed to unravel the second anti-HIV-1 mechanism of WG-am. ResultsThe data suggest that WG-am binds to the CD4 binding pocket of HIV-1 gp120 and blocks its binding to the host cell receptors. Additionally, the time course assay showed that WG-am also inhibited HIV-1 at 4–6 hours post-infection, suggesting a second antiviral mechanism. Drug sensitivity assays under acidic wash conditions confirmed the ability of WG-am to internalise into the host cell in an HIV independent manner. Proteomic studies showed a clustering of all samples treated with WG-am independent of the number of doses or presence or absence of HIV-1. Differentially expressed proteins due to the WG-am treatment indicated an effect on HIV-1 reverse transcription, which was confirmed by reverse transcriptase polymerase chain reaction (RT-PCR). ConclusionNaturally occurring in HIV-1 elite controllers, WG-am stands out as a new kind of antiviral compound with two independent inhibitory mechanisms of action on HIV-1 replication. WG-am halts HIV-1 entry to the host cell by binding to HIV-1 gp120, thereby blocking the binding of HIV-1 to the host cell. WG-am also exerts a post-entry but pre-integration antiviral effect related to RT-activity.

A high durable polysaccharide flame retardant based on phosphorus element for cotton fabrics

A novel polysaccharide flame retardant 2,6-dimethoxy polysaccharide ammonium phosphate (DOPSAP), was synthesized and characterized using nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopy. The characterization results of cotton samples suggested that DOPSAP was successfully grafted onto the cotton fabric through P-O-C covalent bonds. The char length and limiting oxygen index (LOI) of cotton fabrics treated with 30 wt% DOPSAP were 42 mm and 49.4%, and remained at 52 mm and 37.5% after 50 LCs in the violent washing conditions (AATCC 61–2013 3A washing standard), respectively. These results indicated that cotton fabrics treated with DOPSAP had excellent flame retardancy and durability. In the thermogravimetric (TG) analysis, the treated cotton retained 40.8% of the char residual at high temperature under N2 atmosphere. The total heat release (THR) of DOPSAP-treated cotton fabrics reduced from 4.2 to 2.1 MJ/m2 compared to untreated cotton fabrics in the cone calorimetry test. These results showed that DOPSAP inhibited the heat release of cotton fabrics during combustion by promoting the dehydration of cotton fabrics to produce more char, exhibiting a cohesive phase flame-retardant mechanism. The mechanical properties of the treated cotton fabric were remained well. The results showed that the flame retardant with relative high molecule based on polysaccharide and introducing more P element through P-C bonds are effective ways to improve the durability and flame retardancy of treated cotton.

Green remediation of cadmium-contaminated soil by cellulose nanocrystals.

Cellulose nanocrystals (CNC) were used as a novel, green eluent to remediate Cd-contaminated soil in this study. The influence of washing conditions on the removal of Cd, including CNC concentration, pH value, liquid/solid (L/S) ratio, contact time and temperature were investigated. The effect of CNC remediation of Cd-contaminated soil on soil health and the possible remediation mechanism were also explored. The results showed that CNC concentration, pH value and contact time had a significant effect on the removal efficiency of Cd. CNC rapidly removed heavy metals in soil within 30min. When the pH value of the eluent was 9.0, the removal efficiency of Cd could reach 86.3%. The eluent mainly removed exchangeable and reducible fractions of Cd, which could effectively reduce the bioavailability of heavy metals. CNC washing had no negative effects on seed growth, species abundance and Shannon index. C-O, -COO- groups on CNC played an important role in the reaction between CNC and soil Cd, and other oxygen-containing functional groups on CNC could also assist in adsorption, ion exchange and chemical complexation processes. Therefore, cellulose nanocrystals had the potential to remediate heavy metal-contaminated soils in a green and efficient manner.

Tetrapeptide-based mimotope affinity monolith for the enrichment and analysis of anti-HER2 antibody and antibody-drug conjugate

Selective enrichment and analysis of therapeutic antibodies in biological fluids are crucial for the development of biopharmaceuticals. Recently, peptide-based affinity chromatography has exhibited fascinating prospects for antibody enrichment due to the high affinity and specificity of small peptides. However, the post-modification approach of peptide ligands on the material surface is complicated and time-consuming. In this study, a methacrylate modified tetrapeptide (m-EDPW) was firstly demonstrated as the affinity ligand of trastuzumab (Kd = 1.91 ± 1.81 μM). Next, the m-EDPW based affinity monolith was prepared using a facile one-step polymerization method, which could overcome the drawbacks of traditional post-modification preparation strategies. Based on the monolith as described above, a simple enrichment approach was developed under the optimal washing and elution conditions. Based on the excellent properties, such as high porosity (53.09%), weak electrostatic interaction and suitable affinity (1.00 ± 2.14 μM for anti-HER2 ADC), this novel monolith exhibited good specificity and recovery for antibodies (91.6% for trastuzumab, 98.37% for anti-HER2 ADC), and low nonspecific adsorption for human serum albumin (DBC10% = 0.5 mg/g polymer). Particularly, this material was successfully applied to enrich trastuzumab and its related antibody-drug conjugate (ADC) from different cell culture medias. The dynamic tracking analysis of ADC in the critical quality attributes (e.g., charge variants, drug to antibody ratio and subunit conjugation ratio) was also achieved by combining the enrichment approach, capillary electrophoresis or reversed phase liquid chromatography. In summary, the exploited peptide-based mimotope affinity materials showed a great potential for the application in biopharmaceutical analysis.

Investigation of the Functional Ageing of Conductive Coated Fabrics under Simulated Washing Conditions.

Conductive textiles play an important role in recent electronics development; however, one of the major challenges remains their machine-washing durability. For the investigation of the basic wash ageing mechanisms, we used copper-plated polyamide 66 and cellulose fabrics and developed a wet and dry operable flex tester with online resistance recording. The evaluation was supported by abrasion tests, cyclic elongation tests and tribological investigation of dry and wet textile-textile friction. It was found that the contribution of mechanical and chemical ageing to wash ageing strongly depends on the substrate material. A bad adhesion of copper on polyamide 66 leads to early fatigue while better stability of the copper on cellulose leads to a stronger resistance against ageing. For both substrates, the delamination of the copper layer was the root cause of the fatigue, which is facilitated by the washing solution. Finally, a cumulative fatigue model was developed and the determination of the end of lifetime by the intended use is discussed.

Washable PEDOT:PSS Coated Polyester with Submicron Sized Fibers for Wearable Technologies.

The use of non-metallic conductive yarns in wearable technologies like smart textiles requires compliant washable fibers that can withstand domestic washing without losing their conductive properties. A one-pot coating with PEDOT:PSS conductive polymers was applied to polyester submicron fibers, increasing the water resistance and washability under various domestic washing conditions. Plasma treatment of the untreated samples improved the anchoring of the coating to the fibers, producing smooth and homogeneous coatings. The primary doping of PEDOT:PSS with ethylene glycol (EG), dimethyl sulfoxide (DMSO), and a non-ionic surfactant as well as the secondary doping of the composite fibers improved the sheet resistance at room temperature. The as-obtained composite materials showed similar mechanical properties as the parent fibers, indicating that the coating and post-treatment do not affect the overall mechanical property of the composite. The performance of the composites under different temperature and humidity conditions and washability using the standardized ISO 6330:2012 procedure for domestic washing and drying showed that the obtained composites are good candidates for reliable washable wearable technologies, such as all-organic washable Joule heaters in functional textiles.

Evaluation of the detectability of different ages of bloodstains on fabrics in different washing conditions and at various wavelengths

PurposeThe detection of bloodstains at crime scenes is extremely useful in forensic investigations. This study aimed to investigate the effects of washing temperature, fabric type, fabric color, and stain age (time from staining to laundering) on the detection and identification of bloodstains on fabrics after washing. Material and methodA total of 240 fabrics (4 different colors and 5 different types) were stained with blood and washed in 4 different washing temperatures with 3 different lag times. The evaluations of fabric images were performed using the FLS system (Forenscope-Mobile Multispectral UV-VIS-IR Imaging Systems®) on a total of 1200 images using 5 different wavelengths and filter options. The bloodstained areas of the fabric pieces were then excised, and the hemoglobin presence was analyzed using the SERATEC® HemDirect hemoglobin test. ResultsThe analyses of laundered samples using the FLS system revealed that the best images were obtained from velvet, cotton fleece, denim, and polyester fabrics, in that order. Except for polyester fabrics, the SERATEC® HemDirect hemoglobin screening test, which was used to detect bloodstains on fabrics, showed positive results after washing at low temperatures (approximately 15 °C and 30 °C). At higher temperatures (60 °C and 90 °C), the SERATEC® HemDirect hemoglobin test yielded negative results. ConclusionThe fabric type and color played a crucial role in stain detection using the FLS system on the laundered fabrics. The FLS system and the SERATEC® HemDirect hemoglobin test revealed that stain age had a limited effect on the stain's detectability.

Noise-based self-supervised anomaly detection in washing machines using a deep neural network with operational information

To ensure the reliable use and maintenance of a washing machine, condition monitoring and detection of anomalous operations at an early stage are necessary. In this study, we propose a deep neural network architecture for the detection of anomalies in a washing machine based on the noise spectra generated during its operation. Although several self-supervised learning techniques have been developed for the efficient training of an anomaly detection model using only normal data, high diversity in operational noise depending on operating conditions such as laundry weight and imbalance makes anomaly detection in a washing machine difficult. To build a deep neural network model that understands the context of washing conditions and actions, we develop architectures that utilize two types of operational information provided by a washing machine: the spin speed of the drum and laundry weight information. The main self-supervision task of the proposed architecture is to predict the future noise spectrum from the past spectra. However, to utilize the operational information, we investigate two different architectures: one that uses the operational information as a conditioning input to the main task and another that uses it as a secondary objective for a multitask model. Through a cross-validation test with various cloth types and weights, we demonstrate that the proposed architectures can be generalized to various washing machine data and can robustly detect anomalies, even for cloth types unseen during the training stage.

Improvement of RNA In Situ Hybridisation for Grapevine Fruits and Ovules.

The European grapevine (Vitis vinifera L.) is one of the world's most widely cultivated and economically important fruit crops. Seedless fruits are particularly desired for table grapes, with seedlessness resulting from stenospermocarpy being an important goal for cultivar improvement. The establishment of an RNA in situ hybridisation (ISH) system for grape berries and ovules is, therefore, important for understanding the molecular mechanisms of ovule abortion in stenospermocarpic seedless cultivars. We improved RNA in situ hybridisation procedures for developing berries and ovules by targeting two transcription factor genes, VvHB63 and VvTAU, using two seeded varieties, 'Red Globe' and 'Pinot Noir', and two seedless cultivars, 'Flame Seedless' and 'Thompson Seedless'. Optimisation focused on the time of proteinase K treatment, probe length, probe concentration, hybridisation temperature and post-hybridisation washing conditions. The objectives were to maximise hybridisation signals and minimise background interference, while still preserving tissue integrity. For the target genes and samples tested, the best results were obtained with a pre-hybridisation proteinase K treatment of 30 min, probe length of 150 bp and concentration of 100 ng/mL, hybridisation temperature of 50 °C, three washes with 0.2× saline sodium citrate (SSC) solution and blocking with 1% blocking reagent for 45 min during the subsequent hybridisation. The improved ISH system was used to study the spatiotemporal expression patterns of genes related to ovule development at a microscopic level.

Effect of different washing conditions on the removal efficiency of selected compounds in biopolymers

<abstract> <p>Recycling of plastic materials is a key sustainability topic. Hence, the scope of this study is to evaluate the potential of this purification step for achieving high-purity recyclates via mechanical recycling. In this study, the focus is set on the revalorization of poly(3-hydroxy butyrate) and poly(3-hydroxy butyrate-co-3-hydroxy valerate)—two biobased and biodegradable polymers that have properties similar to those of polyolefins and are therefore possible eco-friendly alternatives. Specifically, the washing process as an important part of polymer recycling processes is evaluated regarding different washing conditions on a laboratory scale. For this purpose, several virgin polymers were contaminated with volatile organic compounds that differed in functionality and molecular weight. Regarding contamination, concentration correlates with contamination time. Moreover, the contamination degree was found to be higher for polar contaminants since polar compounds show higher compatibility with the polymer. General beneficial effects of higher temperatures and longer washing times were observed. The choice of washing medium was relevant for different polarities of the contaminants. At higher process temperatures, material degradation occurred. Hence, recyclers have to pay attention to the difference in the interaction between impurities and the polymer and to the degradation of the polymer during recycling and the subsequent formation of degradation products. Since these biopolymers display comparable properties to polyolefins, great potential in packaging applications is apparent. Moreover, the method of analyzing the removal efficiency of volatile organic compounds via washing can be applied to all recyclable polymers.</p> </abstract>

Develop an optimal daily washing care for technical jacket by balancing washing efficiency and functional degradation

In order to reduce the functional degradation caused by improper daily washing-care and prolong the service life of technical jacket, the relationship between the daily washing conditions and functional degradation in the wearing performance of technical jacket (waterproof, windproof, warmth retention) was quantitatively investigated with the help of hydrostatic pressure, surface contact angle, air permeability, warmth retention, and scanning electron microscopy (SEM) of technical jacket after different daily washing conditions. Results showed that no matter what kind of washing modes, washing parameters, type and dosage of detergent, the wearing performance of technical jacket after washing were subjected to decrease compared with pre-washing. Additionally, it was also found that the effects of washing modes, type of detergents and washing parameters on the wearing performance of the technical jacket were significant, instead of the dosage of detergents. This indicates it was possible ways to minimize functional degradation by setting optimal washing conditions (washing parameters, washing mode, types and dosage of detergent). Balancing considerations of functional degradation and washing efficiency, the washing combination of mechanical agitation + micro-nano bubbles), type of detergent (neutral liquid detergent), dosage of detergent (3 g/L), water temperature (20°C), main washing bath ratio (1:10), main washing speed (15 rpm), main washing time (20 min), rinsing speed (30 rpm), rinsing cycles (2), belonged to the optimal washing combination in this study of washing condition. The results were of practical significance to guide manufacturers of washing machine to develop optimal daily washing produce for outdoor clothing, especially technical jacket.

Slippery lubricant-infused silica nanoparticulate film processing for anti-biofouling applications.

Microbial biofilm build-up in water distribution systems can pose a risk to human health and pipe material integrity. The impact is more devastating in space stations and to astronauts due to the isolation from necessary replacement parts and medical resources. As a result, there is a need for coatings to be implemented onto the inner region of the pipe to minimize the adherence and growth of biofilms. Lubricant-infused surfaces has been one such interesting material for anti-biofouling applications in which their slippery property promotes repellence to many liquids and thus prevents bacterial adherence. Textured and porous films are suitable substrate candidates to infuse and contain the lubricant. However, there is little investigation in utilizing a nanoparticulate thin film as the substrate material for lubricant infusion. A nanoparticulate film has high porosity within the structure which can promote greater lubricant infusion and retention. The implementation as a thin film structure aids to reduce material consumption and cost. In our study, we utilized a well-studied nanoporous thin film fabricated via layer-by-layer assembly of polycations and colloid silica and then calcination for greater stability. The film was further functionalized to promote fluorinated groups and improve affinity with a fluorinated lubricant. The pristine nanoporous film was characterized to determine its morphology, thickness, wettability, and porosity. The lubricant-infused film was then tested for its lubricant layer stability upon various washing conditions and its performance against bacterial biofilm adherence as a result of its slippery property. Overall, the modified silica nanoparticulate thin film demonstrated potential as a base substrate for lubricant-infused surface fabrication that repelled against ambient aqueous solvents and as an anti-biofouling coating that demonstrated low biofilm coverage and colony forming unit values. Further optimization to improve lubricant retention or incorporation of a secondary function can aid in developing better coatings for biofilm mitigation.

Antibody Affinity and Stability Maturation by Error-Prone PCR.

Human antibodies are the most important class of biologicals, and antibodies - human and nonhuman - are indispensable as research agents and for diagnostic assays. When generating antibodies, they sometimes show the desired specificity profile but lack sufficient affinity for the desired application. In this article, a phage display-based method and protocol to increase the affinity of recombinant antibody fragments is given.The given protocol starts with the construction of a mutated antibody gene library by error-prone PCR. Subsequently, the selection of high-affinity variants is performed by panning on immobilized antigen with washing conditions optimized for off-rate-dependent selection. A screening ELISA protocol to identify antibodies with improved affinity and an additional protocol to select antibodies with improved thermal stability is described.

A wearable colorimetric sweat pH sensor-based smart textile for health state diagnosis.

Sweat pH is an important indicator for diagnosing disease states, such as cystic fibrosis. However, conventional pH sensors are composed of large brittle mechanical parts and need additional instruments to read signals. These pH sensors have limitations for practical wearable applications. In this study, we propose wearable colorimetric sweat pH sensors based on curcumin and thermoplastic-polyurethane (C-TPU) electrospun-fibers to diagnose disease states by sweat pH monitoring. This sensor aids in pH monitoring by changing color in response to chemical structure variation from enol to di-keto form via H-atom separation. Its chemical structure variation changes the visible color due to light absorbance and reflectance changes. Furthermore, it can rapidly and sensitively detect sweat pH due to its superior permeability and wettability. By O2 plasma activation and thermal pressing, this colorimetric pH sensor can be easily attached to various fabric substrates such as swaddling and patient clothing via surface modification and mechanical interlocking of C-TPU. Furthermore, the diagnosable clothing is durable and reusable enough to neutral washing conditions due to the reversible pH colorimetric sensing performance by restoring the enol form of curcumin. This study contributes to the development of smart diagnostic clothing for cystic fibrosis patients who require continuous sweat pH monitoring.

受关节软骨启发的耐疲劳和耐苛刻环境的三维超弹 海绵导体

Spongy conductors generally suffer from mechanical brittleness and irreversible conductive network damage when subjected to extreme compression and harsh environments. The development of elastic conductors combining the unique characteristics of light weight, super-elasticity, and extraordinary fatigue resistance is massively desired but challenging. Herein, a surface-constrained atomized water templating strategy is presented for fabricating a honeycomb-patterned spongy carbon nanotube conductor (h-SCNTC). By mimicking articular cartilage architecture with gradient energy dissipation under deformation, the resultant h-SCNTC exhibits outstanding compressibility with rapid recovery from deformation (i.e., 0% to 90% compressive strain) and extraordinarily high fatigue resistance (i.e., >95% height retention after 5000 cycles). The developed sensor possesses remarkable features, including superelasticity, durability, and large relative resistance changes across a wide strain range (i.e., 0% to 90%), which can be ascribed to the combination of “connect-disconnect” transition of nanogaps between individual carbon nanotubes in the skeleton under a low compressive strain and compressive contact of the conductive skeletons under a high compressive strain. In particular, the conductor can effectively inhibit water erosion, making it ultradurable against harsh environments in extreme humidity and machine washing conditions. The surface-constrained atomized water templating strategy for fabricating spongy superelastic conductors opens a new avenue to explore the potential of wearable sensors and deformation-tolerant electronics.

Study on the Relationship between Textile Microplastics Shedding and Fabric Structure.

Microplastics refer to plastic fibers, particles or films less than 5 mm in diameter. Textile microplastics are an important form of microplastics, which can harm the ecological environment and human health. This paper studies the relationship between textile microplastic shedding and fabric structure to reduce microplastics pollution and reduce its impact on humans and the natural environment. Firstly, household washing is simulated by considering the main fabric type, the number of steel balls used in the washing, washing temperature, washing time and other influencing factors. An orthogonal test of the mixing level of the four factors is designed by selecting the fabric type, the number of steel balls used in washing, washing temperature and washing time, and the influencing factors is analyzed, and the best washing scheme is obtained. Then, under optimal washing conditions, the three factors and three levels of orthogonal test are designed to analyze the influence of fabric structure and external factors on the shedding of microplastics by changing the amounts of friction and insolation time. The results show that the microplastics released by knitted fabrics are significantly more under the same washing conditions than that of woven fabrics. Satin fabrics released the most microplastics and plain fabrics the least. In addition, among the external factors, the amount of friction significantly affects the production of microplastics.

Comparative Analysis of the Liquid CO2 Washing with Conventional Wash on Firefighters’ Personal Protective Equipment (PPE)

Firefighters are exposed to several potentially carcinogenic fireground contaminants. The current NFPA 1851 washing procedures are less effective in cleaning due to the limited intensity of the washing conditions that are used. The 2020 edition of NFPA 1851 has added limited specialized cleaning for higher efficacy. The liquid carbon dioxide (CO2) laundering technique has gained popularity in recent years due to its availability to remove contaminants and its eco-friendliness. The primary aim of this study is to address the firefighter questions regarding the efficacy of cleaning with liquid CO2 and to compare it with the conventional washing technique. The unused turnout jackets were contaminated with a mixture of fireground contaminants. These turnout jackets were cleaned with conventional NFPA 1851-appoved aqueous washing and a commercially available liquid CO2 method. Post-cleaning samples were analyzed for contamination using pressurized solvent extraction and GC-MS. The liquid CO2 technique demonstrated considerable improvement in washing efficiency compared to the conventional washing.

The survey of soil-transmitted helminth species abundance in Slovakia with an emphasis on parameters important for their distribution.

Soil-transmitted helminths (STH) can be easily dispensable in socially disadvantaged groups. The Roma people represent the group most at risk in Slovakia. This study aimed to investigate the occurrence of STH infections in minorities living with animals under low hygienic conditions and on contaminated soil. Subsequently, we identified the risk assessment factors of the STH transmissions based on parasitological results. In our study, STHs were predominantly found among the Roma communities living in unsanitary conditions. The prevalence of Ascaris lumbricoides among the majority was 0.79%, and Trichuris trichiura was 0.05 %. On the contrary, a community-based cross-sectional survey across eastern Slovakia also found a prevalence of 22.28 and 3.47% for A. lumbricoides and T. trichiura among the Roma population. Inhabitants that belong to the Roma minority had a 37.12 infection OR times higher than non-Roma inhabitants. The Roma people living in the countryside have a 2.23-fold higher chance of getting infected with STH than Roma living in the city. Therefore, soil and domestic animals were also examined for the presence of the STH eggs to show the environmental burden. In general, the presence of STH eggs was confirmed in 26.26% of the soil examined samples. The detailed description is as follows: eggs of Toxocara spp., Trichuris spp., eggs from the family Ancylostomatidae, and Toxascaris leonina. Ascaris eggs were detected only in the soil from localities with low hygienic standards. The probability of contracting the STH eggs in segregated settlements was 15.94 times higher compared to urban or rural areas. In addition to humans, dogs can also be a source of STH eggs in the soil. The STH eggs were confirmed in 43.55% of dog droppings. The most interesting finding was that the eggs of the genus Ascaris were up to 7.93% of dog droppings from localities with a low hygienic standard were positive. This study revealed that climatic factors and the WASH conditions influenced the distribution of STHs to variable degrees. In addition, ethnicity and sanitation were crucial factors in the distribution of STH infection in eastern Slovakia.

Effective soil washing for Cu removal in industrial soil remediation

ABSTRACT Soil contamination caused by heavy metals has become a serious environmental and health-related problem to human. Copper (Cu) is essential to human and plants in appropriate amount but toxicant if excessive. Although soil washing has been developed for a long time for heavy metal remediation, there are few studies focusing on Cu, especially in the case of extreme concentration of metal and dissolved organic matters (DOM). Thus, based on the literature reviews about soil washing, this study tried to find out the practical and effective methods to achieve remediation for Cu pollution in different situations of various soil texture and pollution concentrations. Different Cu polluted soils in industrial ground were sampled in Shanghai for experiments. Considering washing agents, washing duration time, liquid to solid ratio, combinations of different agents and oxidation pretreatment, the optimal soil washing conditions were decided. Results showed that washing agents and soil texture seriously affected the efficiency of soil washing. 0.05 mol/L Ethylenediamine tetraacetic acid (EDTA) or 0.1 mol/L FeCl3 combined with 0.1 mol/L citric acid (CA) was valid for Cu washing for three different soils with removal rate ranged from 68.8 ± 0.8% to 83.2 ± 1.1%. Oxidation pretreatment was necessary when DOM was in high concentration.