scholarly journals Polymer/BiOBr-Modified Gauze as a Dual-Functional Membrane for Heavy Metal Removal and Photocatalytic Dye Decolorization

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2082
Author(s):  
Chi-Jung Chang ◽  
Pei-Yao Chao ◽  
Chen-Yi Chou ◽  
Ying-Jen Chen ◽  
Chih-Feng Huang

It is crucial to remove heavy metals and dyes before discharging industrial effluents. Gauze substrate was surface-modified by coating with a polymeric adsorbent and a spray coating of BiOBr photocatalyst to develop a novel dual-functional membrane, polymer/BiOBr-modified gauze, for water remediation. The polymeric adsorbent was crosslinked to prevent the dissolving of the adsorbent during operation in contaminated water. The morphology and surface chemistry of the modified gauze were characterized before and after the adsorption of Ni2+. The surface wettability, isotherms, and kinetics of Ni2+ adsorption were studied. We also studied the effect of pH, initial Ni2+ concentration, monomer molar ratio, and monomer chemical structure on the Ni2+ adsorption capacity. To achieve a high Ni2+ adsorption capacity and good photocatalytic decolorization activity, the amount of decorated BiOBr was tuned by changing the spray-coating time to optimize the exposed BiOBr and polymer on the surface. The optimized dual-functional membrane PB20 possesses excellent adsorption capacity (650 mg g−1) for Ni2+ ions and photocatalytic decolorization activity (100% degradation of RhB within 7 min). Decorating the optimized amount of BiOBr on the surface can introduce photocatalytic decolorization activity without sacrificing the adsorption capacity for Ni2+.

2020 ◽  
Vol 1010 ◽  
pp. 489-494
Author(s):  
Abdul Hafidz Yusoff ◽  
Rosmawani Mohammad ◽  
Mardawani Mohamad ◽  
Ahmad Ziad Sulaiman ◽  
Nurul Akmar Che Zaudin ◽  
...  

Conventional methods to remove heavy metals from polluted water are expensive and not environmentally friendly. Therefore, this study was carried out to investigate the potential of agricultural waste such as pineapple peel (Ananas Cosmos) as low-cost absorbent to remove heavy metals from synthetic polluted water. The results showed that Cd, Cr and Pb were effectively removed by the biosorbent at 12g of pineapple peels in 100 mL solution. The optimum contact time for maximum adsorption was found to be 90 minutes, while the optimum pH for the heavy metal’s adsorption was 9. It was demonstrated that with the increase of adsorbent dosage, the percent of heavy metals removal was also increased due to the increasing adsorption capacity of the adsorbent. In addition, Langmuir model show maximum adsorption capacity of Cd is 1.91 mg/g. As conclusions, our findings show that pineapple peel has potential to remove heavy metal from polluted water.


2011 ◽  
Vol 383-390 ◽  
pp. 4038-4042 ◽  
Author(s):  
Worathanakul Patcharin ◽  
Kittipalarak Sriamporn ◽  
Anusarn Kanokkan

Bagasse ash is one of the agricultural wastes and valuable biomass by-products in sugar milling. It was treated hydrothermally with hydrochloric aqueous solution at 100 °C and burned at 600°C for 2 hours under oxygen feeding. The obtained white ash was further used as natural silica source instead of silica sol because of highly silica content from an abundant supply of sugar industries in Thailand. Aluminosilicate precursor gel was prepared from alumina source and silica source via sodium silicate preparation. Different crystallization time was studied for the molar ratio of SiO2/Al2O3 = 2 at 100°C crystallization temperature. The phillipsite zeolite synthesized was characterized using various techniques; X-ray diffraction, Scanning electron microscopy, Fourier Transform Infrared Spectroscopy, and BET-N2 adsorption method. The results can be used as value added for bagasse ash utilization, minimize the environmental impact of disposal problems and further application for heavy metal removal.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Rajaa Bassam ◽  
Achraf El hallaoui ◽  
Marouane El Alouani ◽  
Maissara Jabrane ◽  
El Hassan El Khattabi ◽  
...  

The aim of this study is the valorization of the Moroccan clays (QC-MC and QC-MT) from the Middle Atlas region as adsorbents for the treatment of water contaminated by cadmium Cd (II) ions. The physicochemical properties of natural clays are characterized by ICP-MS, XRD, FTIR, and SEM techniques. The adsorption process is investigated as a function of adsorbent mass, solution pH, contact time, temperature, and initial Cd (II) ion concentration. The kinetic investigation shows that the adsorption equilibrium of Cd (II) ions by both natural clays is reached after 30 min for QC-MT and 45 min for QC-MC and fits well to a pseudo-second-order kinetic model. The isotherm study is best fitted by a Freundlich model, with the maximum adsorption capacity determined by the linear form of the Freundlich isotherm being 4.23 mg/g for QC-MC and 5.85 mg/g for QC-MT at 25°C. The cadmium adsorption process was thermodynamically spontaneous and exothermic. The regeneration process showed that these natural clays had excellent recycling capacity. Characterization of the Moroccan natural clays before and after the adsorption process through FTIR, SEM, XRD, and EDX techniques confirmed the Cd (II) ion adsorption on the surfaces of both natural clay adsorbents. Overall, the high adsorption capacity of both natural clays for Cd (II) ions removal compared to other adsorbents motioned in the literature indicated that these two natural adsorbents are excellent candidates for heavy metal removal from aqueous environments.


2021 ◽  
Vol 29 (4) ◽  
pp. 441-448
Author(s):  
Nirjhar Bar ◽  
Tania Mitra ◽  
Sudip Kumar Das

Heavy metal removal from wastewater is a significant research area and recommends sustainable development. The heavy metals cause harmful health effects, increase environmental toxicity. Adsorption is a very effective method for heavy metal removal. A fixed bed for Cu(II) removal using rice hush, an agricultural waste, is reported in this paper. The study was carried out to determine the breakthrough curves with varying operating variables like influent concentration (10–30 mg/L), flow rate (10–40 ml/min), and bed height (4–10 cm) at pH 6. The variation of the process variables like influent concentration, flow rate, and bed height were investigated. The experimental data shows that adsorption capacity increases with the rise of influent concentration. The maximum value of adsorption capacity is 10.93 mg/g at a flow rate of 10 ml/min, bed height 4 cm, and influent concentration 30 mg/L. The applicability of the MLR and ANN modeling has also been successfully carried out. ANN has better predictability than MLR. The findings revealed that rice husk could be used to treat copper-containing industrial effluents.


2015 ◽  
Vol 72 (12) ◽  
pp. 2166-2178 ◽  
Author(s):  
Meng Xu ◽  
Pejman Hadi ◽  
Chao Ning ◽  
John Barford ◽  
Kyoung Jin An ◽  
...  

Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent. It has been demonstrated that when equimolar quantities of the metals are present in wastewater, the adsorbent uptakes the Pb2+ ions selectively. This has been attributed to the higher electronegativity value of Pb2+ compared to Cd2+ which can be more readily adsorbed on the adsorbent surface, displacing the Cd2+ ions. The selectivity can be advantageous when the objective is the separation and reuse of the metals besides wastewater treatment. In non-equimolar solutions, a complete selectivity can be observed up to a threshold Pb2+ molar ratio of 30%. Below this threshold value, the Cd2+ and Pb2+ ions are uptaken simultaneously due to the abundance of Cd2+ ions and the availability of adsorption sites at very low Pb2+ molar ratios. Moreover, the total adsorption capacities of the adsorbent for the multi-component system have been shown to be in the same range as the single-component system for each metal ion which can be of high value for industrial applications.


Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 931 ◽  
Author(s):  
Lu Xia ◽  
Zhonghang Huang ◽  
Lei Zhong ◽  
Fengwei Xie ◽  
Chak Tang ◽  
...  

A novel bio-adsorbent was fabricated via grafting an amino-terminated hyperbranched polymer (HBP-NH2) onto bagasse cellulose. The morphology and microstructure of the HBP-NH2-grafted bagasse cellulose (HBP-g-BC) were characterized and its adsorption capacity for Cr(VI) ions in aqueous solutions was investigated. The rough surface structure of HBP-g-BC that is beneficial for improving the adsorption capacity was observed by scanning electron microscopy (SEM). The grafting reaction was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. The adsorbent performance was shown to be better with a lower pH value, a higher adsorbent dosage, or a higher initial Cr(VI) concentration. Moreover, the kinetics study revealed that the adsorption behavior followed a pseudo-second-order model. The isotherm results showed that the adsorption data could be well-fitted by the Langmuir, Freundlich, or Temkin models. Moreover, HBP-g-BC could maintain 74.4% of the initial removal rate even after five cycles of regeneration. Thus, the high potential of HBP-g-BC as a bio-adsorbent for heavy metal removal has been demonstrated.


Langmuir ◽  
2019 ◽  
Vol 35 (49) ◽  
pp. 16111-16119 ◽  
Author(s):  
Miaomiao Wang ◽  
Kangmin Zhang ◽  
Mingyuan Wu ◽  
Qingyun Wu ◽  
Jiuyi Liu ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wanqi Zhang ◽  
Yuhong An ◽  
Shujing Li ◽  
Zhechen Liu ◽  
Zhangjing Chen ◽  
...  

Abstract Thiol-lignocellulose sodium bentonite (TLSB) nanocomposites can effectively remove heavy metals from aqueous solutions. TLSB was formed by using –SH group-modified lignocellulose as a raw material, which was intercalated into the interlayers of hierarchical sodium bentonite. Characterization of TLSB was then performed with BET, FTIR, XRD, TGA, PZC, SEM, and TEM analyses. The results indicated that thiol-lignocellulose molecules may have different influences on the physicochemical properties of sodium bentonite, and an intercalated–exfoliated structure was successfully formed. The TLSB nanocomposite was subsequently investigated to validate its adsorption and desorption capacities for the zinc subgroup ions Zn(II), Cd(II) and Hg(II). The optimum adsorption parameters were determined based on the TLSB nanocomposite dosage, concentration of zinc subgroup ions, solution pH, adsorption temperature and adsorption time. The results revealed that the maximum adsorption capacity onto TLSB was 357.29 mg/g for Zn(II), 458.32 mg/g for Cd(II) and 208.12 mg/g for Hg(II). The adsorption kinetics were explained by the pseudo-second-order model, and the adsorption isotherm conformed to the Langmuir model, implying that the dominant chemical adsorption mechanism on TLSB is monolayer coverage. Thermodynamic studies suggested that the adsorption is spontaneous and endothermic. Desorption and regeneration experiments revealed that TLSB could be desorbed with HCl to recover Zn(II) and Cd(II) and with HNO3 to recover Hg(II) after several consecutive adsorption/desorption cycles. The adsorption mechanism was investigated through FTIR, EDX and SEM, which demonstrated that the introduction of thiol groups improved the adsorption capacity. All of these results suggested that TLSB is an eco-friendly and sustainable adsorbent for the extraction of Zn(II), Cd(II) and Hg(II) ions in aqueous media.


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