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As the world human population and industrialization keep growing, the water availability issue has forced scientists, engineers, and legislators of water supply industries to better manage water resources. Pollutant removals from wastewaters are crucial to ensure qualities of available water resources (including natural water bodies or reclaimed waters). Diverse techniques have been developed to deal with water quality concerns. Carbon based nanomaterials, especially carbon nanotubes (CNTs) with their high specific surface area and associated adsorption sites, have drawn a special focus in environmental applications, especially water and wastewater treatment. This critical review summarizes recent developments and adsorption behaviors of CNTs used to remove organics or heavy metal ions from contaminated waters via adsorption and inactivation of biological species associated with CNTs. Foci include CNTs synthesis, purification, and surface modifications or functionalization, followed by their characterization methods and the effect of water chemistry on adsorption capacities and removal mechanisms. Functionalized CNTs have been proven to be promising nanomaterials for the decontamination of waters due to their high adsorption capacity. However, most of the functional CNT applications are limited to lab-scale experiments only. Feasibility of their large-scale/industrial applications with cost-effective ways of synthesis and assessments of their toxicity with better simulating adsorption mechanisms still need to be studied.
Mian Aslam; Hsion-Wen Kuo; Walter Den; Muhammad Usman; Muhammad Sultan; Hadeed Ashraf. Functionalized Carbon Nanotubes (CNTs) for Water and Wastewater Treatment: Preparation to Application. Sustainability 2021, 13, 5717 .
AMA StyleMian Aslam, Hsion-Wen Kuo, Walter Den, Muhammad Usman, Muhammad Sultan, Hadeed Ashraf. Functionalized Carbon Nanotubes (CNTs) for Water and Wastewater Treatment: Preparation to Application. Sustainability. 2021; 13 (10):5717.
Chicago/Turabian StyleMian Aslam; Hsion-Wen Kuo; Walter Den; Muhammad Usman; Muhammad Sultan; Hadeed Ashraf. 2021. "Functionalized Carbon Nanotubes (CNTs) for Water and Wastewater Treatment: Preparation to Application." Sustainability 13, no. 10: 5717.
A new type of composite adsorbent, encapsulated chitosan-modified magnetic carbon nanotubes (CS/MWCNTs/Fe) beads were used to remove hexavalent chromium (Cr(VI)) from aqueous solutions in a fixed-bed column. Among the various combination of operating parameters, we obtain a maximum volume of treated effluent (210 mL) under the following conditions: flow rate, 1 mL min−1; bed height, 8 cm; feed Cr(VI) concentration, 30 mg L−1; and solution pH, 4.0 ± 0.2. The corresponding adsorption capacity was 1.54 mg g-1 and the overall Cr(VI) removal efficiency was 54 %. In characterizing the dynamics of the adsorption process and breakthrough profiles, we found that the Thomas model and the Yoon-Nelson model both accurately described the breakthrough curves under all experimental conditions, while the Adams-Bohart model was applicable only for an early phase of dynamic behavior CtC0≤0.5 of the CS/MWCNTs/Fe beads column. Columns with shorter bed heights favored the global mass transfer rate, especially during the early breakthrough periods. Moreover, the bed depth service time (BDST) model was validated experimentally, enabling the prediction of service time of the adsorption bed at different outlet concentrations using hypothetical flow rates and inlet concentrations. Scaled-up study was performed to observe the column performance at higher throughputs. The high selectivity of Cr(VI) adsorption in the simulated wastewater in the presence of other heavy metals (copper and cadmium) and background anion (phosphate) suggests the applicability of CS/MWCNTs/Fe beads for Cr(VI) removal from industrial effluents.
Mian Muhammad Ahson Aslam; Walter Den; Hsion-Wen Kuo. Removal of hexavalent chromium by encapsulated chitosan-modified magnetic carbon nanotubes: Fixed-bed column study and modelling. Journal of Water Process Engineering 2021, 42, 102143 .
AMA StyleMian Muhammad Ahson Aslam, Walter Den, Hsion-Wen Kuo. Removal of hexavalent chromium by encapsulated chitosan-modified magnetic carbon nanotubes: Fixed-bed column study and modelling. Journal of Water Process Engineering. 2021; 42 ():102143.
Chicago/Turabian StyleMian Muhammad Ahson Aslam; Walter Den; Hsion-Wen Kuo. 2021. "Removal of hexavalent chromium by encapsulated chitosan-modified magnetic carbon nanotubes: Fixed-bed column study and modelling." Journal of Water Process Engineering 42, no. : 102143.
This work demonstrates the performance of a composite adsorbent encapsulated with chitosan (CS) and maghemite-doped multiwall carbon nanotubes (MWCNTs). Hexavalent chromium (CrVI) was used as the representative hazardous heavy metal to characterize the adsorption behavior of the composite beads. The chromium speciation chemistry combined with the chitosan surface chemistry rendered pH at 4 to be the optimized condition in which the uptake of CrVI was quantitatively most effective. The Langmuir isotherm with a maximum adsorption capacity of 119 mg g−1 at 298 K was observed. The CrVI adsorption studies using partial compositions of the beads further demonstrated the synergistic role of combining the surface properties of CS and MWCNTs. The CrVI removal efficiency increased from 82 % to 96 % as the CS contents doubled in the CS/MWCNTs/Fe beads. Kinetically, the pseudo-second-order model showed the best regression fit (r2 > 0.99) with the experimental data. The intra-particle diffusion model further elucidated that the multiphasic rate-limiting steps during CrVI adsorption included external mass transfer resistance and intra-particle diffusion. The thermodynamic parameters (ΔG, ΔH, ΔS) indicated the adsorption process was spontaneous and endothermic in the tested temperature range (298–313 K). The weak negative Gibbs free energy (ΔG < −20 kJ mol−1) suggested a spontaneous adsorption process governed by electrostatic adsorption. The evolution of CrIII indicates a possible charge transfer effect of Fe2+/Fe3+ mediated through conductive carbon nanotubes, leading to the reduction of CrVI. In five adsorption-desorption cycles, the CrVI removal efficiency of CS/MWCNTs/Fe beads remained about 80 % in adsorption capacity.
Mian Muhammad Ahson Aslam; Walter Den; Hsion-Wen Kuo. Encapsulated chitosan-modified magnetic carbon nanotubes for aqueous-phase CrVI uptake. Journal of Water Process Engineering 2020, 40, 101793 .
AMA StyleMian Muhammad Ahson Aslam, Walter Den, Hsion-Wen Kuo. Encapsulated chitosan-modified magnetic carbon nanotubes for aqueous-phase CrVI uptake. Journal of Water Process Engineering. 2020; 40 ():101793.
Chicago/Turabian StyleMian Muhammad Ahson Aslam; Walter Den; Hsion-Wen Kuo. 2020. "Encapsulated chitosan-modified magnetic carbon nanotubes for aqueous-phase CrVI uptake." Journal of Water Process Engineering 40, no. : 101793.
Three commercial bio-aid samples have shown good troubleshooting capabilities earlier during several biological wastewaters processing, but their microbial contents were still unclear. This study was aimed to assess eubacteria contents for the three bio-aids based on sequence comparisons of 16S ribosomal deoxyribonucleic acid (rDNA). Majority of target 16S rDNA sequences of bacteria within or cultured from bio-aids were obtained via pyrosequencing-based approach, and few sequences were from isolation- or cloning-sequencing approaches. Results showed that a total of 8114, 2327, and 5402 sequences were retrieved from pyrosequencing-based methods for the three bio-aids, respectively, which were affiliated with 100, 80, and 59 bacterial species based on sequence comparison using Ribosome Data Project (RDP) Classifier and Basic Local Alignment Search Tool (BLAST). Target sequences matched Bacillus sp., Enterococcus sp., and Clostridium sp. of Firmicutes phylum were the most abundant for the bio-aids, while some sequences identical to bacteria of phyla Actinobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, and Proteobacteria were also found. Additionally, most of sequences from the isolation- or cloning-sequencing-based methods were not retrieved by the pyrosequencing-based methods. Culture media appeared to potentially select several bacteria species within phyla Firmicutes and/or Proteobacteria, but sequences from the culture-based methods did fulfill some absences for the uncultured method. Based on principal coordinate analysis, bacteria community structures of the three bio-aids were different. This study provided insights into bacteria contents for the three bio-aids as fundamental information in attempts for future selection or formulation of suitable bio-aids for solving various troubles during wastewater biological processing.
H-W Kuo; C-Y Huang; C-N Chang; P-L Lee; Y-W Chen; H-H Chang; Y-H Tang; S-Z Zeng; G-Y Li; C-R Lin; L-Z Chen. Identification of diverse bacterial communities for potential bio-aids capable of troubleshooting for wastewater biological treatment processes. International Journal of Environmental Science and Technology 2016, 14, 743 -754.
AMA StyleH-W Kuo, C-Y Huang, C-N Chang, P-L Lee, Y-W Chen, H-H Chang, Y-H Tang, S-Z Zeng, G-Y Li, C-R Lin, L-Z Chen. Identification of diverse bacterial communities for potential bio-aids capable of troubleshooting for wastewater biological treatment processes. International Journal of Environmental Science and Technology. 2016; 14 (4):743-754.
Chicago/Turabian StyleH-W Kuo; C-Y Huang; C-N Chang; P-L Lee; Y-W Chen; H-H Chang; Y-H Tang; S-Z Zeng; G-Y Li; C-R Lin; L-Z Chen. 2016. "Identification of diverse bacterial communities for potential bio-aids capable of troubleshooting for wastewater biological treatment processes." International Journal of Environmental Science and Technology 14, no. 4: 743-754.
M.-H. Lin; W.-C. Chen; Y.-L. Liu; H.-W. Kuo; J.-K. Wang; D.-P. Liu. Analyzing a hepatitis A outbreak by integrating space-time distances and network approach as evidences-based assessment of vaccination policy. International Journal of Infectious Diseases 2016, 53, 33 -34.
AMA StyleM.-H. Lin, W.-C. Chen, Y.-L. Liu, H.-W. Kuo, J.-K. Wang, D.-P. Liu. Analyzing a hepatitis A outbreak by integrating space-time distances and network approach as evidences-based assessment of vaccination policy. International Journal of Infectious Diseases. 2016; 53 ():33-34.
Chicago/Turabian StyleM.-H. Lin; W.-C. Chen; Y.-L. Liu; H.-W. Kuo; J.-K. Wang; D.-P. Liu. 2016. "Analyzing a hepatitis A outbreak by integrating space-time distances and network approach as evidences-based assessment of vaccination policy." International Journal of Infectious Diseases 53, no. : 33-34.
This study was aimed to assess seasonal/geographical distribution and sequence diversity of partial hexon gene for human adenoviruses (HAdVs) within raw sewages (RS) and activated sludges (AS). Assessments were based on high‐throughput sequencing (HTS) for polymerase chain reaction (PCR)‐amplified 128‐bp partial hexon gene fragments and followed by principal coordinate analyses (PCoA) for revealed sequences. Sequencing results showed that the majority of sequences (>90%) for the RS or AS samples were identical to HAdV type 41 of species F, while rest of few sequences belonged to HAdV species‐D and –C were only occurred rarely without significant seasonal/geographical variation. The partial hexon genes were highly diverse as many sequence types and operational taxonomic unit groups were noticed among the matched sequences. This study demonstrated that HAdV‐41 was constantly appeared in the RS and AS samples from Taiwan throughout the year without significant seasonal or geographical variations; but, had high sequence diverse noticed for the 128‐bp partial hexon gene fragments. High‐throughput‐sequencing results provided better insights of HAdV distribution and genetic diversity for raw sewage and AS samples allowing some probable biases for cloning‐sequencing approach to be defeated and further providing public health awareness regarding viral‐contaminated sewages or sludges.
H.-W. Kuo; L.-Z. Chen; M.-H. Shih. High prevalence of type 41 and high sequence diversity of partial hexon gene of human adenoviruses in municipal raw sewage and activated sludge. Journal of Applied Microbiology 2015, 119, 1181 -1195.
AMA StyleH.-W. Kuo, L.-Z. Chen, M.-H. Shih. High prevalence of type 41 and high sequence diversity of partial hexon gene of human adenoviruses in municipal raw sewage and activated sludge. Journal of Applied Microbiology. 2015; 119 (4):1181-1195.
Chicago/Turabian StyleH.-W. Kuo; L.-Z. Chen; M.-H. Shih. 2015. "High prevalence of type 41 and high sequence diversity of partial hexon gene of human adenoviruses in municipal raw sewage and activated sludge." Journal of Applied Microbiology 119, no. 4: 1181-1195.
Isolating cellulase-secreting microbes followed-by screening their cellulolytic activities has been an essential approach to discover novel and potential cellulases for cellulolytic industrial applications. This study was aimed to explore competitive exoglucanases by screening avicelase activities for 92 fungal strains isolated from environmental airborne-fungal-spore samples. Results showed that an isolated fungal strain numbered 58 exhibited the best avicelase activity of 0.209 U/mL when cultured for six days at pH 5.0 - 5.3 and 25℃ - 27℃, and was lately identified as a yeast strain of Meyerozyma sp. (96% ITS fragment similar with Meyerozyma caribbica, HG970748). Based on amino acid sequences revealed from LC/MS/MS, the target exoglucanase was identical to 1,4-beta-D-glucan cellobiohydrolases and was named Mc-CBHI which had optimal avicelase reaction conditions of pH 5 and 70℃ and could remain fairly stable after 4hr incubation at acid conditions (pH 3 - 5) or wide temperature ranges (30℃ - 80℃). Additionally, the Mc-CBHI (~70 kDa and ~3.6% of crude enzyme) had specific FPase and avicelase activities of 0.179 U/mg and 0.126 U/mg, respectively (which were about 40% - 50% activities of a commercial cellulase Accellerase-1000). These results demonstrated that the newly-found Mc-CBHI could become one of potential exoglucanase resources for related cellulolytic industrial applications.
Hsion-Wen Kuo; Jia-Kun Zeng; Pi-Han Wang; Wen-Chin Chen. A Novel Exo-Glucanase Explored from a Meyerozyma sp. Fungal Strain. Advances in Enzyme Research 2015, 03, 53 -65.
AMA StyleHsion-Wen Kuo, Jia-Kun Zeng, Pi-Han Wang, Wen-Chin Chen. A Novel Exo-Glucanase Explored from a Meyerozyma sp. Fungal Strain. Advances in Enzyme Research. 2015; 03 (03):53-65.
Chicago/Turabian StyleHsion-Wen Kuo; Jia-Kun Zeng; Pi-Han Wang; Wen-Chin Chen. 2015. "A Novel Exo-Glucanase Explored from a Meyerozyma sp. Fungal Strain." Advances in Enzyme Research 03, no. 03: 53-65.
Y C Lo; W C Chen; W T Huang; Y C Lin; M C Liu; H W Kuo; J H Chuang; J R Yang; M T Liu; H S Wu; C H Yang; J H Chou; F Y Chang. Surveillance of avian influenza A(H7N9) virus infection in humans and detection of the first imported human case in Taiwan, 3 April to 10 May 2013. Eurosurveillance 2013, 18, 1 .
AMA StyleY C Lo, W C Chen, W T Huang, Y C Lin, M C Liu, H W Kuo, J H Chuang, J R Yang, M T Liu, H S Wu, C H Yang, J H Chou, F Y Chang. Surveillance of avian influenza A(H7N9) virus infection in humans and detection of the first imported human case in Taiwan, 3 April to 10 May 2013. Eurosurveillance. 2013; 18 (20):1.
Chicago/Turabian StyleY C Lo; W C Chen; W T Huang; Y C Lin; M C Liu; H W Kuo; J H Chuang; J R Yang; M T Liu; H S Wu; C H Yang; J H Chou; F Y Chang. 2013. "Surveillance of avian influenza A(H7N9) virus infection in humans and detection of the first imported human case in Taiwan, 3 April to 10 May 2013." Eurosurveillance 18, no. 20: 1.