Insights into the mechanically resilient, well-balanced polymeric membranes by incorporating Rhizophora mucronata derived activated carbon for sustainable wastewater decontamination

International audienceIn this study, hydrophilic activated carbon has been prepared and used to synthesize innovative activated carbon/polysulfone mixed matrix membranes (MMMs). These membranes were investigated in terms of membrane morphology, hydrophilicity, antifouling ability, and metal ions rejection. The activated carbon (AC) was prepared from a simple chemical activation method using Rhizophora mucronata propagules, which are rich in aerenchyma cells and possess a high surface area. The hydrophilicity of the MMMs is enhanced by the incorporation of activated carbon, which is confirmed by the measurement of equilibrium water contact angle, water uptake and pure water flux. The optimized concentration of 0.625 wt% activated carbon (A2) incorporated mixed matrix membrane exhibits better rejection efficiencies of 98 ± 0.5%, 99 ± 0.5%, 92 ± 2%, and 44 ± 1% for Pb+2, Cd+2, Hg+2, and F− with the permeate flux of 28.27, 31.88, 33.21, 43.82 L/m2/h, respectively. The fabricated mixed matrix membranes demonstrated an excellent flux recovery ratio and reversible fouling, when filtrating a mixed feed solution containing 200 ppm BSA, 10 ppm Pb+2 and 10 ppm Cd+2. The optimized A2 membrane showed excellent long-term stability up to 120 h without compromising in permeate flux and rejection efficiency. Finally, a numerical investigation using a usual transport model has shown that dielectric exclusion was the most probable mechanism that can physically explain experimental trends

Recent advances in microfluidic platform for physical and immunological detection and capture of circulating tumor cells

CTCs (circulating tumor cells) are well-known for their use in clinical trials for tumor diagnosis. Capturing and isolating these CTCs from whole blood samples has enormous benefits in cancer diagnosis and treatment. In general, various approaches are being used to separate malignant cells, including immunomagnets, macroscale filters, centrifuges, dielectrophoresis, and immunological approaches. These procedures, on the other hand, are time-consuming and necessitate multiple high-level operational protocols. In addition, considering their low efficiency and throughput, the processes of capturing and isolating CTCs face tremendous challenges. Meanwhile, recent advances in microfluidic devices promise unprecedented advantages for capturing and isolating CTCs with greater efficiency, sensitivity, selectivity and accuracy. In this regard, this review article focuses primarily on the various fabrication methodologies involved in microfluidic devices and techniques specifically used to capture and isolate CTCs using various physical and biological methods as well as their conceptual ideas, advantages and disadvantages.Department of Science & Technology | Ref. TDP/BDTD/32/2019Department of Science and Technology | Ref. DST/TDT/DDP-31/2021Taif University | Ref. TURSP-2020/04European Commission | Ref. H2020, n. 89422

Mg–Al-Layered Double Hydroxide (LDH) Modified Diatoms for Highly Efficient Removal of Congo Red from Aqueous Solution

In this work, diatomaceous earth (DE) or diatoms are modified with Mg–Al-layered double hydroxide (DE-LDH) using the facile co-precipitation method to demonstrate their application for the removal of toxic dyes such as Congo Red (CR), which was used as a model. Field emission scanning electron microscopy (FE-SEM) characterization confirms the successful modification of diatom microcapsules structures, showing their surface decorated with LDH nano patches with sheet-like morphologies. The surface area of the DE was enhanced from 28 to 51 m2/g after modification with LDH. The adsorption studies showed that the maximum CR removal efficiency of DE and DE-LDH was ~15% and ~98%, respectively at pH 7, which is a significant improvement compared with unmodified DE. The maximum adsorption capacities of DE-LDH were improved ten times (305.8 mg/g) compared with the bare DE (23.2 mg/g), showing very high adsorption performances. The recyclability study of DE-LDH up to five cycles, after desorbing CR either by methanol or by NaOH, showed the efficient removal of the CR by up to three cycles via adsorption. The presented study suggests the promising application of DE-LDH as an effective material for application in the removal of CR from aqueous solutions for industrial wastewater treatment

Ceria decorated porous diatom-xerogel as an effective adsorbent for the efficient removal of Eriochrome Black T

Diatomaceous earth or diatom (DE) are naturally available and low cost micro particles with distinct porous structure were used as an adsorbent for the removal of a hazardous dye, Eriochrome Black T (EBT). The surface modification of these DE were performed by sol-gel and hydrothermal methods to obtain a series of adsorbents such as diatom-ceria (DC), diatom-silica xerogel (DX), and diatom-silica xerogel-ceria (DXC). A cauliflower like morphology structure of ceria was observed on DE and DX. The adsorption performance of EBT was conducted by varying various parameters such as pH, adsorbent dosage, initial concentration, contact time and ionic strength. The materials DE, DC, DX and DXC showed the EBT removal efficiencies of 52, 77, 20, and 93%, respectively. The maximum adsorption capacity (qm) of DE, DC, DX and DXC was found to be 13.83, 23.64, 0.2 and 47.02 mgg for the adsorption of EBT, respectively. The selectivity of EBT towards DXC was evaluated by treating a mixture of anionic dyes. The dye removal experiments was performed in presence of inorganic salts, however the presence of these salts did not affect the removal efficiency of DXC. Furthermore, the reusability of DXC was studied by recycling it up to 5 times and even at 5th cycle a removal efficiency of ∼66.8% was found. Thus, these studies demonstrate that the DXC material could be a promising candidate for the removal of EBT via adsorption for real time application in water treatment

Amine activated diatom xerogel hybrid material for efficient removal of hazardous dye

The effective removal of organic pollutants from aqueous media is still an eminent challenge. In the present work, naturally available diatomaceous earth (DE) particles was surface modified with mesoporous silica xerogel denotes as diatom xerogel material. Subsequently amine functionality has been successfully introduced on diatom xerogel (DXEA) for the efficient removal of hazardous dye, Eriochrome Black T (EBT). The adsorbents before and after EBT adsorption were characterized using various techniques such as XRD, FE-SEM, FTIR and BET. The adsorption process was conducted by varying many parameters such as pH, dosage, initial concentration of dye and time. The designed adsorbent, DXEA showed increased removal efficiency (∼99 %) in comparison with neat DE (∼58 %) due to the presence of amine functional group, which favours the rapid adsorption of EBT. This study showed that adsorbent DXEA was adequate to remove 50 mg/L and 100 mg/L of aqueous EBT in 5 and 60 min of contact time respectively. The maximum dye adsorption capacity of DXEA was found to be ∼62 mg/g whereas, for DE it was ∼56 mg/g. The dye adsorption kinetics of EBT onto both the DXEA and the DE follow the pseudo-second-order model. Also, DXEA was used for selective removal of EBT in the presence of other dyes and recycle studies were discussed. These studies showed that DXEA is a promising material for EBT removal by adsorption in real sample

Naturally available diatomite and their surface modification for the removal of hazardous dye and metal ions: a review

The presence of toxic pollutants such as dyes and metal ions at higher concentrations in water is very harmful to the environment. Removal of these pollutants using diatomaceous earth or diatomite (DE) and surface-modified DE has been extensively explored due to their excellent physio-chemical properties and low cost. Therefore, naturally available DE being inexpensive, their surface modified adsorbents could be one of the potential candidates for the wastewater treatment in the future. In this context, the current review has been summarized for the removal of both pollutants i.e., dyes and metal ions by surface-modified DE using the facile adsorption process. In addition, this review is prominently focused on the various modification process of DE, their cost-effectiveness; the physio-chemical characteristics and their maximum adsorption capacity. Further, real-time scenarios of reported adsorbents were tabulated based on the cost of the process along with the adsorption capacity of these adsorbents

Real-time probe for the efficient sensing of inorganic fluoride and copper ions in aqueous media

A highly sensitive and efficient rhodamine 6G based probe (P3 ) was synthesized for the real‐time sensing of F⁻ and Cu²⁺ ions. The probe P3 was able to show significant color change from brown to pink in the presence of F⁻ and yellow to orange in presence of Cu²⁺ ions. The UV‐vis studies confirm that the probe P3 was able to detect F⁻ and Cu²⁺ ions over other ions. Further, UV‐vis titration studies were carried out to understand the detection mechanism and stoichiometry between P3 : F⁻ and P3 : Cu²⁺ ions. ¹H‐NMR titration was performed to confirm the F⁻ ion binding to probe P3 , where, deprotonation of hydrazone proton (‐C=N‐NH ‐) was observed. In addition, the limit of detection for P3 :F⁻ and P3 :Cu²⁺ ions were found to be 4.02 μM and 1.64 μM respectively which is useful for practical applications. Lastly, probe P3 was used to detect and quantify the F⁻ ions present in a commercially available mouthwash product. Furthermore, P3 was adsorbed on the surface of silica microsphere to detect Cu²⁺ ions. Interestingly, the material could visually detect 1 ppm of Cu²⁺ ions which is lower than the permissible limit.Pravin Patil, Kanalli V. Ajeya, Mahesh P. Bhat, Ganesan Sriram, Jingxian Yu, Ho-Young Jung, Tariq Altalhi, Madhuprasad Kigga, and Mahaveer D. Kurkur