Chemical Fiber Research Articles

Preparation and Characterization of Microporous Cellulose Membranes as Potential Pathogen Filters

Growth and development in the textile and fashion industry have resulted in the generation of large amounts of industrial pre-consumer textile wastes. It is estimated that 10 to 20% of textile fabrics are wasted during garment manufacturing, with most of the wastes being burned or landfilled. Reusing pre-consumer fabric wastes is therefore considered a viable approach to alleviate environmental impacts associated with their disposal. To achieve a higher porosity membrane, pre-consumer cotton fabrics were partially dissolved in a solution of dimethyl acetamide (DMAc) and lithium chloride (LiCl), and the resulting fibre suspension was utilized to prepare a microporous cellulose membrane (MCM) through a vacuum filtration method. The suspension comprised a mixture of partially and completely dissolved fibres, which provided the required morphological and structural integrity to the fibrous membranes. The membranes’ chemical structure, fibre size, and morphology were characterized based on Fourier transform infrared spectroscopy (FT-IR), light microscope, and field emission scanning electron microscopy (FE-SEM), respectively. The filtration efficiency of the microporous cellulose membranes was evaluated against 500 ppm sodium chloride (NaCl) solutions. The results showed that the filtration efficiency of the membranes ranged between 31.82 and 59.85% for cellulose membranes with 60.2% porosity, suggesting that the membranes could be applied as filters against pathogens upon further improvement.

Research and demonstration on reclaimation of chemical industrial wastewater with high salinity and hardness and purification of reverse osmosis concentrates

The demonstration is specifically designed to achieve the reclaimation of integrated chemical industry park wastewater (CIPWW) with high levels of hardness and salinity and the standardized discharge of concentrates generated during the reclaimation period by effectively composing dual-membrane technology combined by microfiltration (MF) and reverse-osmosis (RO) with multiple water treatment techniques. Concerning the concentrates generated by RO, the full-scale calcium-sulfate (CaSO4) crystallizer is creatively applied as the pretreatment unit for hardness removal with doubled catalytic ozonation-high performance biological aerated filter (O3-HBAF) and ultrafiltration (UF) as subsequent treatment technologies. Considering the characteristics of RO concentrates as high permanent hardness, high sulfate concentration and high refractory organic matter (ROM) content, pilot tests were conducted particularly focusing on the CaSO4 crystallizer and O3-HBAF unit which verified the reasonability of the technological process, and relevant operating parameters were optimized including flocculant dosage, catalyst dosage, etc. A series of adjustments were also made for the agent-addition devices of RO in order to stabilize the differential pressure facing variable influent circumstances. During over one-year of full-scale operation, the treated CIPWW was innovatively supplied for chemical fiber factories which established rigorous limitations on the impurity content of reuse water, and the water quality of purified RO concentrates partially met the requirements of class IV of Environmental Quality Standard for Surface Water (GB3838–2002, China). The application of CaSO4 crystallizer approximately saved the operation cost by 57.04 % compared with that of Na2CO3 softening process, and sufficiently recycled calcium ions from RO concentrates as CaSO4·2H2O products.

Matrix-entrapped fibers create ecological niches for gut bacterial growth

Insoluble plant cell walls are a main source of dietary fiber. Both chemical and physical fiber structures create distinct niches for gut bacterial utilization. Here, we have taken key fermentable solubilized polysaccharides of plant cell walls and fabricated them back into cell wall-like film forms to understand how fiber physical structure directs gut bacterial fermentation outcomes. Solubilized corn bran arabinoxylan (Cax), extracted to retain some ferulate residues, was covalently linked using laccase to form an insoluble cell wall-like film (Cax-F) that was further embedded with pectin (CaxP-F). In vitro fecal fermentation using gut microbiota from three donors was performed on the films and soluble fibers. Depending on the donor, CaxP-F led to higher relative abundance of recognized beneficial bacteria and/or butyrate producers—Akkermansia, Bifidobacterium, Eubacterium halii, unassigned Lachnospiraceae, Blautia, and Anaerostipes—than free pectin and Cax, and Cax-F. Thus, physical form and location of fibers within cell walls form niches for some health-related gut bacteria. This work brings a new understanding of the importance of insoluble cell wall-associated fibers and shows that targeted fiber materials can be fabricated to support important gut microbiota taxa and metabolites of health significance.

Effects of the green finance policy on the green innovation efficiency of the manufacturing industry: A difference-in-difference model

This study examined the impact of green finance policy on the green innovation efficiency (GIE) of the manufacturing industry in China based on data between 2005 and 2019 using a difference-in-difference model. The results indicate that implementing the green finance policy reduced the GIE of heavy-polluting industries compared with that of non-heavy-polluting industries. In terms of industry-specific heterogeneity, the green finance policy had a significant negative effect on the GIE of the textile industry, non-metallic mineral products industry, ferrous and non-ferrous metal smelting and rolling processing industry, chemical fiber manufacturing industry, metal product industry, leather and other related industries, and pharmaceutical manufacturing industry. However, it had a significant positive effect on the GIE of the chemical raw material and chemical product manufacturing industry, agricultural and sideline food processing industry, and papermaking and paper product industry. Furthermore, it also promotes the GIE of environment-friendly industries. In terms of factor heterogeneity, the green finance policy has had a positive effect on GIE improvement in technology- and capital-intensive industries. Moreover, it has inhibited GIE improvement in labor-intensive industries. To promote the GIE in manufacturing, a series of policy recommendations have been put forward.

Predicting the in vitro dissolution rate constant of mineral wool fibers from fiber composition

Objective We developed predictive formulae for the in vitro dissolution rate constant kdis of acid-soluble synthetic vitreous fibers (SVF), paralleling our earlier work with glass wools, which are typically more soluble at neutral pH. Developing simple models for predicting the kdis of a fiber can allow prediction of in vivo behavior, aid fiber developers, and potentially reduce in vivo testing. Methods The kdis of several acid-soluble SVF were determined using high simulant fluid flow/fiber surface area (F/A) conditions via a single-fiber measurement system. Four fluids were employed, varying in base composition and citrate levels. Equations predicting the kdis were derived from fiber chemistry and dissolution measurements for two of the fluids. Results Testing of several fibers showed a ∼10× increase in the kdis when citrate was included in the simulant solution. Data from tests with Stefaniak’s citrate-free Phagoloysosmal Simulant Fluid (PSF) yielded kdis values aligned with expectations from in vivo results, unlike results from citrate-containing modified Gamble’s solution. Predictive equations relating fiber chemistry to kdis showed reasonable agreement between the measured and predicted values. Conclusions Citrate inclusion in the solution under high F/A conditions significantly increased the measured kdis. This resulted in more biorelevant data being obtained using the PSF fluid with the high F/A method used. The developed predictive equations, sufficient for fiber development work, require refinement before a recommending their use in place of in vivo biopersistence testing. Significant fit improvements are possible through additional measurements under these experimental conditions.

Enhancement of Mechanical, Thermal and Morphological Properties of Eleusine Indica Grass Fiber Reinforced Epoxy Composites

ABSTRACT This research focuses on developing a new material by reinforcing chemically treated Eleusine Indica (EI) fiber with epoxy resin as matrix. Composites using varying wt% of treated EI fibers were fabricated taking epoxy as matrix. The effect of chemical treatment and fiber loading on various mechanical properties, thermal, and morphology using a scanning electron microscope (SEM) was investigated. From the results obtained, it is obvious that the mechanical and thermal properties of composites reinforced with chemically treated fibers were enhanced due to fiber surface modification which helps in better bonding with matrix. Moreover, the composites with 20 wt% fiber concentration shows good tensile strength, Young’s modulus, impact strength and was found to be 79.31MPa, 3.84 GPa, 32.24 KJ/m2 respectively. At this fiber loading the composites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric (TGA) and compared with untreated fiber reinforced composites and neat epoxy. Finally, the failure analysis of fracture surface due to delimitation, pull-out of the fibers, percentage of voids, and composite fracture has been verified using scanning electron microscope. The findings provide manufacturers and engineers with a general concept of how to employ the composites to make low-weight automotive parts for improved fuel efficiency.

PENETRATION AND REPELLENCY OF CHEMICAL PROTECTIVE COVERALLS

Present study was to evaluate chemical penetration and repellency of locallymanufactured protective coveralls used by the workers of fertilizer manufacturing units. The researchwas based on laboratory work performed and completed at Dyeing and Finishing Unit, Nishat MillsLimited. The samples were evaluated for their chemical resistance at various laundering intervals byISO 6530:2005 test methods. Chemical penetration and repellency of three different fabrics were testedagainst four different chemicals. The results showed that all the samples were unable to resist chemicalattack and their condition, became even worse with repeated washing cycles. At 20th washing cycle,98.5% chemicals penetrated synthetic fiber (polyester) whereas chemical penetration for blended fiberwas recorded at 98.9% and for natural fibers was recorded at 99.1%. Similarly chemical repellency fornatural and synthetic fiber was recorded at 0% whereas for blended it was recorded 1at 0.4%.According to the test results, out of all the three samples, synthetic fiber performed better againstchemical attacks.

Temporal and Spatial Trajectories of the Economic and Pollution Emission Focus of China's Textile Industry

Correctly handling the relationship between economic development and pollution emissions in the textile industry is an important basis for achieving green and sustainable economic development in the textile industry. This paper takes the textile industry as the research object, selects the textile industry micro data from 1998 to 2013, firstly uses the centre of gravity model to explore the spatial and temporal trajectory of the centre of gravity of the textile industry's economy and pollution emission; then uses the grey correlation method to measure the correlation between the textile industry and six sub-sectors in two dimensions of economic development and pollution emission; finally uses the centre of gravity coupling posture model to explore the coupling posture of the centre of gravity of the textile industry's economy and the centre of gravity of pollution emission The results show that: (1) from 1998 to 2013, the economic centre of gravity of the textile industry was always located within the Anhui provincial boundary; and the output value of the cotton, chemical fibre textile and dyeing and finishing industries had the greatest impact on the economic growth of the textile industry. (2) The centre of gravity of the textile industry's pollution emissions from 1998-2013 moved along Shanxi-Henan-Hubei-Shaanxi to the western region; the pollution emissions from the manufacture of textile manufactured goods and the cotton, chemical fibre textile and dyeing finishing industries were the main factors causing the pollution problems in the textile industry; (3) From 1998 to 2013, the coupling between the textile economy and the centre of gravity of pollution emissions showed a "W"-shaped trend change, and was influenced by the strategy of shifting the centre of gravity of the textile industry to the west. The purpose of this paper is to provide theoretical suggestions for the green development of the textile industry economy by studying the relationship between the textile industry economy and the focus of pollution emissions.

APPLICATION OF FIBROUS MATERIALS WITH SORPTION PROPERTIES IN WATER PURIFICATION TECHNOLOGIES

The algorithm for the technological process of obtaining a chemisorption composite material based on waste chemical fibers filled with clay powders for the purification of wastewater from heavy metal ions has been developed. Non-woven mate-rials obtained from polyurethane-polyamide chemical fiber waste were used as a basis in the work. To increase the mechanical strength, they were fastenedby the needle punching method with a knitted fabric with a surface density of 240g/m2, which was made by plaited weaving using cotton yarn with a linear density of 25 texand polyethylene complex threads with a linear density of 16.5 tex on a single-font circular knitting machine of the MS type. To strengthen the sorption capacity, clay powders of the montmorillonite type were introduced into the fibrous base in the form of filled dispersions of starch (2-3%) or polyvinyl alcohol (3%) in the amount of 5 to 10% of the mass of the dispersion.Sorption-filtering fibrous material filled with clay minerals can be used for wastewater treatment of light and chemical industry enterprises. The use of clay minerals through their introduction into the fibrous base will reduce the hydraulic re-sistance of the sorbent layer, without using a sorbent of coarse fractions, which will preserve the area of the active absorbing surface. Wastewater treatment can be carried out by passing water through a sorption-filtering element. Cleaning installations can accommodate several sorption-filtering elements at the same time, which increases the efficiency of water purification. It is possible to usechemisorption composite material for cleaning silted drains without the threat of adsorbent clogging, and in return water supply systems, which will reduce the risk of depositing mineral salts on the walls of water purification equipment and ensure high-quality operation of treatment facilities.

Infrared nanospectroscopy depth-dependent study of modern materials: morpho-chemical analysis of polyurethane/fibroin binary meshes.

Infrared scattering-type scanning near-field optical microscopy (IR s-SNOM) and imaging is here exploited together with attenuated total reflection (ATR) IR imaging and scanning electron microscopy (SEM) to depict the chemical composition of fibers in hybrid electrospun meshes. The focus is on a recently developed bio-hybrid material for vascular tissue engineering applications, named Silkothane®, obtained in the form of nanofibrous matrices from the processing of a silk fibroin-polyurethane (SFPU) blend via electrospinning. Morphology and chemistry of single fibers, at both surface and subsurface level, have been successfully characterized with nanoscale resolution, taking advantage of the IR s-SNOM capability to portray the nanoscale depth profile of this modern material working at diverse harmonics of the signal. The applied methodology allowed to describe the superficial characteristics of the mesh up to a depth of about 100 nm, showing that SF and PU do not tend to co-aggregate to form hybrid fibers, at least at the length scale of hundreds of nanometers, and that subdomains other than the fibrillar ones can be present. More generally, in the present contribution, the depth profiling capabilities of IR s-SNOM, so far theoretically predicted and experimentally proven only on model systems, have been corroborated on a real material in its natural conditions with respect to production, opening the room for the exploitation of IR s-SNOM as valuable technique to support the production and the engineering of nanostructured materials by the precise understanding of their chemistry at the interface with the environment.

Sensory and chemical evaluation of laboratory ensiled hybrid Napier grass prepared using Lactobacillus plantarum and propionic acid as additives

The present study was undertaken to evaluate silage made from hybrid Napier grass (Pennisetum purpureum) ensiled in the laboratory using various additives with regard to sensory as well as chemical characteristics. Four different silages were prepared viz., grass ensiled without additives (GS) as control, and grass silage with Lactobacillus plantarum at 1 x 105 CFU per gram of fresh forage (GSL), grass silage with propionic acid at the rate 0.45 kg per ton of fodder (GSA), and grass silage with combination of Lactobacillus plantarum (1 x 105 CFU per gram of fresh forage) and propionic acid (0.45 kg per ton of fodder) (GSLA) in triplicates. One from each triplicate was opened on 21, 30 and 45 days of ensiling and was evaluated for sensory (colour, aroma, presence or absence of extraneous matter) and chemical (pH, lactic acid, proximate analysis and fibre fractions) characteristics. From the overall results, it could be concluded that hybrid Napier grass, ensiled for 21 days using L. plantarum was effective in preserving its nutritive value.

An Edge-Fog-Cloud Computing-Based Digital Twin Model for Prognostics Health Management of Process Manufacturing Systems

The prognostics health management (PHM) from the systematic view is critical to the healthy continuous operation of process manufacturing systems (PMS), with different kinds of dynamic interference events. This paper proposes a three leveled digital twin model for the systematic PHM of PMSs. The unit-leveled digital twin model of each basic device unit of PMSs is constructed based on edge computing, which can provide real-time monitoring and analysis of the device status. The station-leveled digital twin models in the PMSs are designed to optimize and control the process parameters, which are deployed for the manufacturing execution on the fog server. The shop-leveled digital twin maintenance model is designed for production planning, which gives production instructions from the private industrial cloud server. To cope with the dynamic disturbances of a PMS, a big data-driven framework is proposed to control the three-level digital twin models, which contains indicator prediction, influence evaluation, and decision-making. Finally, a case study with a real chemical fiber system is introduced to illustrate the effectiveness of the digital twin model with edge-fog-cloud computing for the systematic PHM of PMSs. The result demonstrates that the three-leveled digital twin model for the systematic PHM in PMSs works well in the system's respects.

Evaluation of the reliability of the qualitative forensic method "Microscopic examination of textile fibers"

Methods of qualitative analysis are widely used in various spheres of public activity, including forensic examination. Making the right decisions based on the results of qualitative analysis, necessitates confirmation of the reliability (uncertainty) of the methods which can be provided by the validation procedure. However, the issues related to the validation of qualitative forensic methods are debatable in the absence general regulatory requirements for qualitative analysis methods. We consider a validation procedure of the qualitative forensic technique “Microscopic examination of textile fibers,” which consists in determining a complex of characteristic external features of natural and chemical textile fibers (color, color features, morphological features) using a microscope, as well as thickness and presence/absence of a matting agent for chemical fibers. These generic characteristics are used to differentiate the fibers under study in the forensic examination of fibrous materials. The reliability of the methodology and the competence of the performers were selected as validation parameters. The parameters were determined numerically by the likelihood ratio and by the values of the share of false and correct results in the total number of tests. Ten samples of natural and chemical textile fibers from the comparative collection of the Laboratory of forensic examination of fibrous materials of the RFCSE were used for validation. Three experts participated in the experiment independently identified the presence/absence of ten external signs in each of ten samples during a week. Each expert tested a set of one hundred different external features, 39 of them were present in the samples, and 61 were absent. When comparing the test results obtained by the expert with the corresponding regulated (known) external features, a conclusion was made about the level of true or false result for each sample. A low (1.7%) level of false results was revealed in relation to the total number of tests, as well as a low (2.6%) level of false results for each of the experts indicated the reliability of the methodology and competence of the experts. The calculation of the likelihood ratio (LR) showed that the probability of true results in the assessment of a set of features is about 60 times (significantly more than one) higher than the probability of false results, which also indicates the reliability of the technique. The results of the validation experiment allowed us to conclude that the method is suitable for use in solving expert problems in the forensic examination of fibrous materials.

Can TEMPO-Oxidized Cellulose Nanofibers Be Used as Additives in Bio-Based Building Materials? A Preliminary Study on Earth Plasters

Interest towards cellulose nanofibers obtained from virgin and waste sources has seen a significant growth, mainly thanks to the increasing sensitivity towards the concept of circular economy and the high levels of paper recycling achieved in recent years. Inspired by the guidelines of the green building industry, this study proposes the production and characterization of TEMPO-oxidized and homogenized cellulose nanofibers (TOHO CNF) from different sources and their use as additives for earth plasters on two different raw earth samples, characterized by geotechnical laboratory tests and mineralogical analysis: a high-plasticity clay (T2) and a medium-compressibility silt (ABS). Original sources, including those derived from waste (recycled cardboard and paper mill sludge), were characterized by determining chemical content (cellulose versus ashes and lignin) and fiber morphology. TOHO CNF derived from the different sources were compared in terms of nanofibers medium diameter, crystallinity degree, thermal decomposition and oxidation degree, that is the content of carboxylic groups per gram of sample. Then, a preliminary analysis of the influence of CNF on earth plasters is examined. Adhesion and capillary absorption tests highlighted the effect of such nanofibers on blends in function of two factors, namely the cellulose original source and the oxidation degree of the fibers. In particular, for both earth samples, T2 and ABS, a significant increase in adhesion strength was observed in the presence of some TOHO CNF additives. As far as capillary sorption tests, while an undesired increase in water adsorption was detected for T2 compared to the control, in the case of ABS, a significant reduction in water content was measured by adding TOHO CNF derived from recycled sources. These results pave the way for further in-depth investigation on the role of TOHO CNF as additives for earth plasters.

Modification of fly ash physicochemical properties for using in dispersionhardened bitumen-based pavement

One of the ways is substantiated to solve the most important environmental problems currently arising in the development and functioning of the heat and power complex. The first is the elimination of fly ash dumps formed during coal combustion. The second is utiliza tion of fibrous sorbents exhausted during the elimination of emergency oil spills, products, shale tars, coal fuses. It is shown that fine ash and asphalt-concrete compositions reinforced with chemical fibers obtained from end-of-life fibrous sorbents, can be used in the pavement construction. The number of properties of hydraulic fly ash and neutralization of sesquioxides contained in them are improved. The latter are catalysts for oil bitumen aging. It is shown that the proposed solutions lead to a decrease in the bitumen content in the fly ash, increase in average density, decrease in porosity and true density. This provides its use in construction of reinforced pavements without increasing the oil bitumen consumption. Highly active components contained in petroleum products neutralize the ability of sesquioxides to accelerate the aging process of petroleum bitumen, which is confirmed by IR spectroscopy.

Improved sample storage, preparation and extraction of blueberry aroma volatile organic compounds for gas chromatography

Aroma profiles of blueberries contain a heterogeneous mixture of volatile organic compounds (VOCs), and headspace sampling is the most efficient approach to VOC extraction from berries. Typically, headspace solid-phase microextraction (HS-SPME) has been applied to blueberry VOCs. Though HS-SPME has been the most common choice for headspace sampling, the fiber chemistry introduces selectivity to the extraction: preferential sorption may skew aroma profiles. Dynamic headspace (DHS) is an attractive substitute for HS-SPME, given its improved sensitivity and lessened bias imparted due to extraction phase selectivity. DHS extractions tend to yield a larger number of compounds and require even less sample than HS-SPME. These two extraction techniques were applied to homogenized blueberries and extracts were subjected to analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS). Major chemical classes were identified with filtering scripts for GC×GC-TOFMS data. The HS-SPME and DHS methods were assessed for reproducibility and chemical diversity (i.e., recovered chemical classes).

Optimization of endoglucanase-lipase-amylase enzyme consortium from Thermomyces lanuginosus VAPS25 using Multi-Objective genetic algorithm and their bio-deinking applications

In this study, the enzyme consortium of endoglucanase, lipase, and amylase was obtained and optimized using artificial intelligence-based tools. After optimization using a multi-objective genetic algorithm and artificial neural network, the enzyme activity was 8.8 IU/g, 153.68 U/g, and 19.2 IU/g for endoglucanase, lipase, and amylase, respectively, using Thermomyces lanuginosus VAPS25. The highest enzyme activity was obtained at parameters 77.69% moisture content, 52.7 °C temperature, 98 h, and 3.1 eucalyptus leaves: wheat bran ratio. The endoglucanase-lipase-amylase (END-LIP-AMY) enzyme consortium showed reliable characteristics in terms of catalytic activity at 50–80 °C and pH 6.0–9.0. The increase in deinking efficiency of 27.8% and 11.1% were obtained compared to control for mixed office waste and old newspaper, respectively, using the enzyme consortium. The surface chemical composition and fiber morphology of deinked pulp was investigated using Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and Scanning electron microscopy (SEM).

Recent progress in biobased synthetic textile fibers

The use of synthetic fibers in our daily life is growing continuously; however, the excessive dependence of these chemical fibers on petroleum-based chemicals will lead to large consumption of non-renewable resources. The scarcity of oil resources, economic and environmental problems, reliance on a few oil-rich countries, and predicted depletion of these resources. Therefore, research and development of biobased materials to reduce the use of fossil fuels have become increasingly important. Biobased synthetic fiber has a low carbon footprint in the synthesis process because its raw materials are derived from biomass. In addition, most biobased synthetic fibers have excellent biodegradability, which can be composted and degraded in natural environments or by microorganisms with or without specific conditions. However, all biobased fibers cannot be proven to be biodegradable, so the development of biodegradability is an important driving force for the progress of research on biobased fibers. In the past, biobased fiber was obtained, extracted, or synthesized from food crops, which was soon replaced by non-food crops. With environmental protection, sustainability, and resource conservation, it has become necessary to make non-food crops and food residues biobased raw materials to obtain biobased textile fibers and even to develop ideal biobased raw materials that are carbon negatives, such as moss and CO2. Besides, there is huge potential for these biobased textile fibers to be used for sustainable clothing and medical textiles due to their non-toxicity, skin friendliness, and antibacterial properties. This review paper introduces biobased synthetic textile fibers, summarizes the recent development, and clarifies key concepts in this domain.

CHARACTERIZATION OF CHEESTNUT SHELL

The outer brownish shell (pericarp) of sweet chestnut (Castanea sativa Mill.) was characterized in terms of chemical composition and fiber morphology. Chestnut fruits were collected from Amasra, Bartin-Türkiye. The cottony structure was removed before the analyses. Main lignocellulose compounds were determined as 45.3% holocellulose, 29.2% α-cellulose, 42.5% Klason lignin, and 3.2% extractives. Analytical results showed that MeOH:Water (95:5 v/v) extract contained 23.8% Fructose, 16% Glucitol, and 11.2% Glucose. Gallic acid was found only 5% in the acetone:water extract. The fiber length, fiber width, lumen width, and fiber wall thickness of the samples were measured as 1.52 mm, 21.67 µm, 14.25 µm, and 3.71 µm, respectively. Chestnut shells, which are morphologically similar to hardwood fibers and contain a high amount of lignin, have significant potential for use as raw materials in different industries.

In situ chemical oxidation-grafted amidoxime-based collagen fibers for rapid uranium extraction from radioactive wastewater

The development of an amidoxime (AO)-based biomass adsorbent offers a solution for uranium extraction from radioactive wastewater and seawater. It also provides a strategy for realizing environmental safety and resource sustainability. Here, an AO-based collagen fiber (CF) adsorbent (AO-CF) was fabricated via in situ oxidative grafting. The fibrous morphology enables AO-CF to realize faster adsorption rate and higher adsorption capacity. During batch adsorption, the adsorption capacity of AO-CF was 0.877 mmol g−1 (234.16 mg g−1) at 318 K and pH 5.0 when the initial concentration of UO22+ was 2.5 mmol/L, while the adsorption capacity of AO-CF at pH 8.2 was 1.128 mmol g−1 (301.18 mg g−1). Moreover, AO-CF exhibited high selectivity for UO22+ in bilateral mixed solutions, including NH4+, Zn2+, Cr3+, Mg2+, Al3+, Ca2+, Ni2+, Ba2+, and Sr2+. Furthermore, AO-CF demonstrated higher adsorption capacity of UO22+ than its major competing element, namely, VO2+, in seawater. The adsorption behavior of UO22+ in the nuclear fuel preparation wastewater on the AO-CF column showed that the breakthrough point was approximately 175.0 bed volume (BV), and the AO-CF column could be rapidly regenerated by using only 3.0 BV of 0.1 mol/L HCl solution, indicating excellent reapplication ability. This work presents a new technology for the synthesis of highly efficient adsorbents for the recovery of UO22+ from radioactive wastewater.