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SEM graphs of free cells and immobilized C09V beads (a) free cells 20 000Â; (b) free cells with CV and Cu(II) 20 000Â; (c) free cells with CV and Cr(VI) 20 000Â; (d) immobilized cells 5000Â; (e) immobilized cells with CV and Cu(II) 5000Â; and (f) immobilized cells with CV and Cr(VI) 5000Â.
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A new functional biomaterial based on Burkholderia vietnamiensis C09V (C09V) was immobilized on beads and used for simultaneous removal of both heavy metals and crystal violet (CV). The results showed that removal of CV and metal ions using immobilized cell bead (biomaterial) was more efficient than that of free cells, wherein 89.4% of CV and 64.1%...
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... SEM. The SEM graphs in Fig. 4(a)-(c) revealed that the morphology of free cells before and aer the adsorption of CV and heavy metals. Fig. 4(a) showed the free cells control sample, which had a smooth surface and shaped size was about 1 mm  0.5 mm. 3 The micrograph in Fig. 4(c) depicted that the cell surface structure was destroyed compared with that in Fig. 4(a). ...
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... SEM. The SEM graphs in Fig. 4(a)-(c) revealed that the morphology of free cells before and aer the adsorption of CV and heavy metals. Fig. 4(a) showed the free cells control sample, which had a smooth surface and shaped size was about 1 mm  0.5 mm. 3 The micrograph in Fig. 4(c) depicted that the cell surface structure was destroyed compared with that in Fig. 4(a). This may be attributed to that Cu(II) was attached to the func- tional groups on the surface of cells and the ...
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... SEM. The SEM graphs in Fig. 4(a)-(c) revealed that the morphology of free cells before and aer the adsorption of CV and heavy metals. Fig. 4(a) showed the free cells control sample, which had a smooth surface and shaped size was about 1 mm  0.5 mm. 3 The micrograph in Fig. 4(c) depicted that the cell surface structure was destroyed compared with that in Fig. 4(a). This may be attributed to that Cu(II) was attached to the func- tional groups on the surface of cells and the existence of Cu(II) may affect the morphological and physiological characteristics of the microorganism. 27 However, in comparison to Fig. ...
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... SEM graphs in Fig. 4(a)-(c) revealed that the morphology of free cells before and aer the adsorption of CV and heavy metals. Fig. 4(a) showed the free cells control sample, which had a smooth surface and shaped size was about 1 mm  0.5 mm. 3 The micrograph in Fig. 4(c) depicted that the cell surface structure was destroyed compared with that in Fig. 4(a). This may be attributed to that Cu(II) was attached to the func- tional groups on the surface of cells and the existence of Cu(II) may affect the morphological and physiological characteristics of the microorganism. 27 However, in comparison to Fig. 4(c), the cell in Fig. 4(b) show a complete structure. It was assumed that part of ...
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... in Fig. 4(c) depicted that the cell surface structure was destroyed compared with that in Fig. 4(a). This may be attributed to that Cu(II) was attached to the func- tional groups on the surface of cells and the existence of Cu(II) may affect the morphological and physiological characteristics of the microorganism. 27 However, in comparison to Fig. 4(c), the cell in Fig. 4(b) show a complete structure. It was assumed that part of Cr(VI) could be reduced to Cr(III) when it was combined with binding sites, resulting in a lower toxicity within the solution. Fig. 4(d) showed that the cells could grow in PVA-SA-kaolin beads. 3 As shown in Fig. 4(e) and (f), the cell density was still high ...
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... that the cell surface structure was destroyed compared with that in Fig. 4(a). This may be attributed to that Cu(II) was attached to the func- tional groups on the surface of cells and the existence of Cu(II) may affect the morphological and physiological characteristics of the microorganism. 27 However, in comparison to Fig. 4(c), the cell in Fig. 4(b) show a complete structure. It was assumed that part of Cr(VI) could be reduced to Cr(III) when it was combined with binding sites, resulting in a lower toxicity within the solution. Fig. 4(d) showed that the cells could grow in PVA-SA-kaolin beads. 3 As shown in Fig. 4(e) and (f), the cell density was still high inside the beads aer ...
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... existence of Cu(II) may affect the morphological and physiological characteristics of the microorganism. 27 However, in comparison to Fig. 4(c), the cell in Fig. 4(b) show a complete structure. It was assumed that part of Cr(VI) could be reduced to Cr(III) when it was combined with binding sites, resulting in a lower toxicity within the solution. Fig. 4(d) showed that the cells could grow in PVA-SA-kaolin beads. 3 As shown in Fig. 4(e) and (f), the cell density was still high inside the beads aer the CV and heavy metals reaction, indicating that the immobilization provided a protective effect to microorganisms. 22 This further illustrated that the immobi- lized cells could act as a ...
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... of the microorganism. 27 However, in comparison to Fig. 4(c), the cell in Fig. 4(b) show a complete structure. It was assumed that part of Cr(VI) could be reduced to Cr(III) when it was combined with binding sites, resulting in a lower toxicity within the solution. Fig. 4(d) showed that the cells could grow in PVA-SA-kaolin beads. 3 As shown in Fig. 4(e) and (f), the cell density was still high inside the beads aer the CV and heavy metals reaction, indicating that the immobilization provided a protective effect to microorganisms. 22 This further illustrated that the immobi- lized cells could act as a functional biomaterial for removal of dye and heavy metals. Fig. 5(a)-(f) for ...
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The adsorption of lead from polluted aqueous solutions was investigated using a biosorbent, without chlorophyll, obtained from Opuntia larreyi cactus in batch mode. The biomaterial was characterized using Fourier Transformed Infrared spectroscopy (FTIR), before and after contact with lead; in addition, the interaction between oxygen atoms from func...
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... Three major additional peaks were observed on the spectrum of NIC + CV (Fig. 7b). These peaks which shifted slightly after the adsorption of CV, were attributed to C--C stretching (benzene ring), C-N stretching (Aromatic tertiary amine), C -N stretching (Tertiary amine), and appeared at 1594, 1370 and 1168 cm − 1 respectively [67][68][69]. This implies that there is an interaction between CV and NIC. ...
... The obtained spectrum corresponds to that of pure water. No characteristic peak of the CV or MB was observed in the spectrum which is indicative of complete chemical degradation of the MB and CV in simpler compounds, such as carbon dioxide and water [28,29]. ...
This work aimed to investigate photocatalytic properties of GQDs@PEG@Mg–ZnFe2O4 nanocomposite, composed of graphene quantum dots (GQDs), polyethylene glycol (PEG), and Mg–ZnFe2O4, for the degradation of methylene blue (MB) and crystal violet (CV). This nanocomposite was synthesized using facile ultrasonics-assisted methodology. XRD analysis confirmed the formation of the spinel structure of the Mg–ZnFe2O4 in the nanocomposite, whereas the presence of GQDs and PEG was confirmed by Fourier transform infrared spectroscopy. Scanning electron microscopy (SEM) revealed a reduction in agglomeration and particle size in the ternary nanocomposite. The GQDs@PEG@Mg–ZnFe2O4 nanocomposite demonstrates a remarkable degradation efficiency of 98 % for CV and MB dyes in the presence of sunlight in 120 min, indicating its potential as an efficient photocatalyst. Vibrating sample magnetometer (VSM) analysis confirmed the superparamagnetic behavior of the GQDs@PEG@Mg–ZnFe2O4 nanocomposite which enables magnetic recovery of the photocatalyst after the degradation process. Overall, this study emphasizes the utilization of an environmentally friendly approach to effectively eliminate organic pollutants from wastewater, addressing a crucial environmental concern.
... Các dao động đặc trưng của composite trước hấp phụ, sau hấp phụ và sau khi giải hấp phụ [8], [19]. Các số sóng ở 1589,2-1592,1 cm -1 và 1368,3-1381,6 cm -1 là các dao động của liên kết N-H và C-H của CV [20], chứng tỏ composite đã hấp phụ các ion CV + . Sự xuất hiện của nhóm chức T-O-T tại số sóng 779,1 cm -1 (Hình 5c) là do trong quá trình giải hấp một số ion CV + đã bị đẩy ra khỏi composite. ...
Nghiên cứu này giới thiệu quy trình tổng hợp composite zeolite/MNPs đơn giản ở điều kiện tổng hợp: tỷ lệ khối lượng giữa MNPs:zeolite = 1:4 (w/w), tỷ lệ ethanol:H2O = 10:1 (v/v), 5 mL tetraethyl orthosilicate (TEOs), 90oC và 4 giờ. Các phương pháp phân tích XRD, FTIR và SEM nhằm xác định sự hiện diện của MNPs và zeolite với hình dạng, kích thước và sự phân bố khá đồng đều. Thành phần hóa học của composite được phân tích bằng XRF với hàm lượng SiO2; Al2O3 và Fe2O3 là 41,11%; 27,75% và 30,78%. Đánh giá khả năng xử lý crystal violet (CV) được thực hiện ở điều kiện pH ~ 7, khối lượng composite 0,75 g/L, nồng độ CV 100 mg/L và thời gian 30 phút, dung lượng và hiệu suất hấp phụ lần lượt là 103,37 mg/g và 70,64%. Quá trình hấp phụ CV phù hợp với mô hình đẳng nhiệt Sips và mô hình động học Elovich. Cơ chế của quá trình là hấp phụ trên bề mặt không đồng nhất và hấp phụ vật lý. Hiệu suất hấp phụ CV của composite giảm từ 70,64% đến 42,26% sau 5 chu kỳ. Các kết quả trên cũng cho thấy tiềm năng ứng dụng của composite zeolite/MNPs trong xử lý nước thải chứa thuốc nhuộm hữu cơ.
... FTIR spectra of biogenic minerals revealed vibrational peaks at -OH, -CH, and -SH at 3412, 2968, and 579 cm − 1 , indicating the presence of a large amount of polysaccharide and protein-based organic materials in the two biominerals (Argun and Dursun, 2008;Cheng et al., 2016). Meanwhile, the vibrational peaks of vaterite were observed at 1083, 876, and 747 cm − 1 (Liu and Lian, 2019b). ...
... The peaks at 867 and 587 cm − 1 are attributed to Nb-O stretching vibration [71], and the peak at 3419 cm − 1 is attributed to N-H stretching vibrations. The peaks at 2905, 1591, 1370, 1168, and 1021 cm − 1 are assigned to C-H stretching (CH 3 group), C--C stretching (benzene ring), C-N stretching (Aromatic tertiary amine), C-N stretching (Tertiary amine) and C-C bond, respectively [72][73][74]. The spectra of the Nb OX500 , Nb EG500 and Nb PEG500 present a slight difference after the CV adsorption. ...
Niobium pentoxide (Nb2O5) nanoparticles have attracted attention in recent years due to their enhanced adsorption and photocatalysis properties against emerging contaminants. The photocatalytic properties of niobium pentoxide are directly related to defects and non-stoichiometric phases in its structure. This work presents the synthesis of Nb2O5 nanoparticles using the Pechini method and precursor decomposition techniques. X-ray diffraction (XRD) showed the presence of niobium pentoxide crystallized in TT, T, H, and the non-stoichiometric Nb12O29 phases. The samples calcined at 500 °C showed a specific surface area (SSA) between 55 and 65 m² g⁻¹, acting as a good adsorbent and photocatalyst to degrade crystal violet (CV). The contaminant adsorption process was studied and optimized using zeta-potential analysis, showing a negatively charged surface at pH > 2, with optimal adsorption at pH = 10. The adsorption study showed the best fit for the adsorption isotherm proposed by Liu and also the possibility of reusing Nb2O5. The photodegradation of crystal violet dye using Nb2O5 as catalyst showed synergetic properties, in which samples with higher SSA and crystallization in the TT-phase decolored the solution in 2 h 30 min. However, the mixture of H–Nb2O5 and Nb12O29 also showed good adsorption properties and decolored the CV pollutant in 2 h 30 min, demonstrating that adsorption and photodegradation mechanisms strongly depend on the crystalline phase of the niobium pentoxide.
... The OH vibration peaks are at wavenumbers of 3600-2500, 3414, and 2360 cm − 1[53]. The peak at 2963 cm − 1 represents the vibrations of C-H[54]. The peaks at 1639 and 1618 cm − 1 represent the vibrations of C--O[54,55].The absorption peaks at 894 and 760 cm − 1 evince the hydrogen bonds between the weak water bond ( ...
... The peak at 2963 cm − 1 represents the vibrations of C-H[54]. The peaks at 1639 and 1618 cm − 1 represent the vibrations of C--O[54,55].The absorption peaks at 894 and 760 cm − 1 evince the hydrogen bonds between the weak water bond ( ...
The research and development of high-efficiency biological mineral materials for the treatment of heavy metal pollution is key to the remediation of heavy metal pollution. Biogenic struvite (BS) was synthesized using microbial culture technique, and a batch adsorption experiments and mineral characterization methods were performed to evaluate the immobilization effect of BS on Cd(II) and the phase transformation in this process. The results show that Bacillus velezensis can regulate the synthesis of irregular BS containing about 14.21% organic matter in Luria-Bertani medium. The adsorption of BS on Cd(II) can be better fitted by the Langmuir equation (R² = 0.9990), Qmax = 282.96 mg/g. The adsorption kinetics and hermodynamics show that the adsorption of Cd(II) by BS is a spontaneous exothermic chemisorption process with increased chaos. Furthermore, the adsorption capacity of BS on Cd(II) is always maintained at about 174.35 mg/g with pH ≥ 3. Furthermore, the part of Cd(II) combines with organic functional groups on the BS to form Cd-containing complexes or chelates, and the part of Cd(II) partially displaces Mg²⁺ and NH4⁺ from struvite crystals to form Cd-bearing phosphate minerals. In summary, the superior immobilization capacity of BS on Cd(II) is attributed to the organic-inorganic structure of BS, complexation or chelation effect, crystal ion exchange, phase transformation, and the formation of secondary phosphate minerals, which makes it difficult to desorb Cd(II). The results offer new ideas for the research and development of new materials for heavy metal pollution remediation.
... For the application of fungi biomass in large-scale processes, immobilization of biosorbent is a necessary step to increase the efficiency of metal adsorption on the surface of biomass, the removal and recovery of metals, as well as to regenerate and reuse the biosorbent in subsequent cycles. The free microbial cells are generally small particles that have low density, poor mechanical strength and little rigidity, which may cause solid-liquid separation problems, possible biomass swelling, inability to regenerate/reuse, clogging of filter parts and a reduction in high pressure required to generate suitable flow rates in a packed or fluidized column mode [5,35,36]. To address these issues, microbial biomass immobilization systems, including entrapment, adsorption, cross-linking, covalent bonding to the carrier and encapsulation, have been studied [5,[37][38][39][40][41][42][43][44][45][46]. ...
Biosorption has been considered a promising technology for the treatment of industrial effluents containing heavy metals. However, the development of a cost-effective technique for biomass immobilization is essential for successful application of biosorption in industrial processes. In this study, a new method of reversible encapsulation of the highly pigmented biomass from Aspergillus nidulans mutant using semipermeable cellulose membrane was developed and the efficiency of the encapsulated biosorbent in the removal and recovery of copper ions was evaluated. Data analysis showed that the pseudo-second-order model better described copper adsorption by encapsulated biosorbent and a good correlation (r ² > 0.96) to the Langmuir isotherm was obtained. The maximum biosorption capacities for the encapsulated biosorbents were higher (333.5 and 116.1 mg g ⁻¹ for EB10 and EB30, respectively) than that for free biomass (92.0 mg g ⁻¹ ). SEM-EDXS and FT-IR analysis revealed that several functional groups on fungal biomass were involved in copper adsorption through ion-exchange mechanism. Sorption/desorption experiments showed that the metal recovery efficiency by encapsulated biosorbent remained constant at approximately 70% during five biosorption/desorption cycles. Therefore, this study demonstrated that the new encapsulation method of the fungal biomass using a semipermeable cellulose membrane is efficient for heavy metal ion removal and recovery from aqueous solutions in multiple adsorption-desorption cycles. In addition, this reversible encapsulation method has great potential for application in the treatment of heavy metal contaminated industrial effluents due to its low cost, the possibility of recovering adsorbed ions and the reuse of biosorbent in consecutive biosorption/desorption cycles with high efficiency of metal removal and recovery.
... Although many adsorbents have been proposed for the adsorption of metallic and organic contaminants, finding a suitable porous sorbent tending towards both organic and metallic compounds is challenging [11]. There are some studies on the removal of Cr(VI) and CV from aqueous systems by adsorption processes using different adsorbents, e.g., rarasaponin-bentoniteactivated biochar [10], and immobilized stains as functionalized biomaterial [12]. In addition, there are some relevant studies, such as the adsorption of Pb(II) and CV using nanoparticle sorbents derived from modified rice husk and copolymer [13], adsorption of Cr(VI) and methyl orange by quaternary ammonium salt modified magnetic chitosan composite [14], adsorption of Cr(VI), methylene blue and direct red 81 using metal-organic framework [15], and removal of Pb(II) and malachite green via magnetic activated carbon and cobalt nanoparticles [16]. ...
... where E a is the activation energy (J/mol), and K is the kinetic constant. Because of the high agreement with the experimental data, the pseudo-second order model constant (K 2 ) was chosen for the kinetic constant in equation (12). Therefore, the activation energy was determined by plotting ln(K 2 ) versus 1/T, and the results are shown in Table 5. ...
The present study deals with the adsorption of chromium oxyanions (Cr(VI)) as a metallic pollutant and Crystal Violet (CV) dye from an aqueous solution. Silica Pillared Clay (SPC) was prepared using the sol-gel method by SiO2 pillaring agent and cationic surfactant template. The main results of the pillaring process were the significant increase in specific surface area (40 to 600 m²/g), pore volume (0.13 to 1.43 cm³/g), and the formation of a mesopore structure. The powdered SPC was granulated by a combination of biopolymers (alginate and chitosan), which led to a decrease in SBET to 455 m²/g and the addition of functional groups (amine and carboxyl). The best pH for Cr(VI) adsorption was 3; however, CV adsorption varied slightly by pH. GBP-SPC's maximum monolayer adsorption capacities for Cr(VI) and CV were 66.33 and 208.9 mg/g, respectively. The kinetic studies showed the higher initial sorption rate of CV (29 mg/g.h) compared to Cr(VI) (18 mg/g.h). The adsorption of Cr(VI) was exothermic with an activation energy of 22.08 kJ/mol; in contrast, the adsorption of CV was endothermic with an activation energy of 13.95 kJ/mol, both in the range of physical adsorption. The higher affinity of GBP-SPC towards CV is related to the same behavior in the raw clay and SPC. Due to their permanent negative charge structure, these samples showed higher attraction towards cationic dye. Binary solution adsorption revealed that the presence of CV had a negligible negative effect on Cr(VI) uptake, whereas CV adsorption was significantly improved in the presence of Cr(VI).
... Cd 2þ might have arisen because Cd 2þ displaced Ca 2þ and Mg 2þ from the HMC lattice and combined it with CO 3 2-. The characteristic peaks at 3398,2962,2929,2368,1654,1240, and 594 cm À1 corresponded to O-H, C-H, CH 2 , C¼O, COOand S-H functional groups, respectively (Argun and Dursun 2008;Cheng et al. 2016;Frost et al. 2015;Lv et al. 2017;Quintelas et al. 2009). After adsorbing Cd 2þ , the peak positions of organic functional groups on the mineral surface shifted to 3411,2960,2927,2364,1652,1240 and 574 cm À1 respectively. ...
... After adsorbing Cd 2þ , the peak positions of organic functional groups on the mineral surface shifted to 3411,2960,2927,2364,1652,1240 and 574 cm À1 respectively. The shift was the result of the interaction between Cd 2þ and functional groups, indicating that the complex or chelate containing cadmium had formed (Cheng et al. 2016;Quintelas et al. 2009). ...
Biogenic carbonates usually differ significantly both in physical and chemical characteristics from those of the same chemical origin, and heavy metal immobilization is prominent among these differences. In this research, a biosynthetic method of high-magnesium calcite (HMC) generated by Bacillus velezensis (B. velezensis) in the presence of humic acid (HA) was developed to ascertain the immobilization characteristics of biogenic high-magnesium calcite (BHM) for Cd²⁺. The study showed that the presence of HA was crucial to the formation of crystalline BHM. The Cd²⁺ immobilization assay results indicated that significant amounts of Cd²⁺ could be adsorbed and the obtained data could fit the Langmuir equation (R² = 0.98, Qmax = 65.36 mg/g), and the adsorption process conformed to the pseudo-second order kinetic model (R² = 0.99). In particular, BHM can maintain the adsorption capacity at above 100 mg/g even under acidic conditions (pH ≥ 3). Further analysis showed that the adsorption was mainly monolayer physical adsorption, and a small amount of chemisorption also occurred. Thermodynamic parameters (ΔG > 0, ΔH > 0, and ΔS < 0) indicated that the adsorption process was a non-spontaneous endothermic reaction. XRD and SEM-EDS analyses demonstrated that the culture precipitate obtained was mainly HMC, with numerous 10-nm pores based on Barrett-Joyner-Halenda theory of surface area. The results of TG-DTG/DTA analysis showed that the BHM contained about 31.31 ± 3.77% organic matter. Amorphous CdCO3 and the complex or chelate bearing Cd²⁺ formed in adsorption process could ensure low desorption, implying a novel prospect for remediation of heavy metal pollution using BHM.
... The iron oxide nanoparticles synthesized were characterized by X-ray diffraction (XRD) to confirm its formation (Fig. 2). The X-ray diffraction pattern of the synthesized nanoparticles was found to match with that reported in the literature [54] (JCPDS No. 33-663) by which we found out that they were hematite nanoparticles. It was observed that there were few peaks which we could decipher and the peaks were not very sharp which may be due to impurities. ...
Heavy metal pollution has become one of the most significant environmental problems globally leading to ecological imbalance. There are many physicochemical and biological methods for the removal of heavy metals. Most of the physicochemical methods are less eco-friendly and less cost-effective, while the biological methods are slow in nature. Recently, nanoparticles have been suggested as efficient alternatives to existing treatment methods, in both resource conservation and environmental remediation of anthropogenic compounds. Nanotechnologies are pervasive solution vectors in our economic environment. Biological synthesis of nanoparticles has grown markedly to create novel materials that are eco-friendly, cost-effective and stable with great importance in wider application in the areas of electronics, medicine and agriculture. Thus, the current work focuses on a comparative remediation of heavy metals using physical, chemical and biological methods and nano-structured copper iodide is used as an adsorbent for the removal of chromium (Cr) and zinc (Zn). In the present study, we have experimented with a few methods in physical (UV light irradiation, adsorption studies using CuI), chemical (UV photocatalysis using CuI) and biological methods (using co-culture bacteria strains). A combination of chemical and biological methods was also probed using CuI–polyvinyl alcohol nano-composite containing bacterial co-cultures. The synthesized nano-composite was characterized using scanning electron microscope. The present study revealed that the most effective and cost-friendly method was using biologically prepared nano-composite of CuI (a combination of both chemical and biological methods) to remediate heavy metals Cr and Zn with a removal efficiency up to ~ 67% for Cr and ~ 55% for Zn at the end of 48 h.
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