Recent progress of metal organic frameworks-derived composites in adsorptive removal of pharmaceuticals

Tetracycline decontamination from aqueous media using nanocomposite adsorbent based on starch-containing magnetic montmorillonite modified by ZIF-67

In the present study, starch/zeolitic imidazole framework-67 (ZIF-67) modified magnetic montmorillonite nanocomposite adsorbent to remove tetracycline (TC) as an emerging antibiotic-based contaminant from aqueous media. The surface properties of the adsorbents were investigated using FTIR, XRD, SEM, EDX-Map, XPS, TEM, BET, and VSM analysis. The specific surface area of MMT, St/MMT-MnFe2O4, and St/MMT-MnFe2O4-ZIF-67 magnetic nanocomposite samples were found to be 15.63, 20.54, and 588.41 m2/g, respectively. The influence of pH, adsorbent amount, initial TC concentration, temperature, contact time, and coexisting ions on TC elimination was explored in a batch adsorption system. The kinetic and equilibrium data were well matched with the pseudo-second-order and Langmuir isotherm models, respectively. The maximum monolayer adsorption capacities of TC were obtained to be 40.24, 66.1, and 135.2 mg/g by MMT, St/MMT-MnFe2O4, and St/MMT-MnFe2O4-ZIF-67 magnetic nanocomposite adsorbents, respectively. Also, thermodynamic studies illustrated that the TC adsorption process is exothermic and spontaneous. Furthermore, the magnetic nanocomposite adsorbent St/MMT-MnFe2O4-ZIF-67 showed good reusability and could be recycled for up to five cycles. This excellent adsorption performance, coupled with the facile separation of the magnetic nanocomposite, gave St/MMT-MnFe2O4-ZIF-67 a high potential for TC removal from aqueous media.

Fabrication of Bacterial Cellulose/Chitosan-MIL-100(Fe) Composite for Adsorptive Removal of Dacarbazine

In this research, a polymeric composite based on a chitosan/bacterial cellulose (CS/BC) matrix filled with MIL-100(Fe) particles was prepared to solve the recyclability of issue MIL-100(Fe) particles and utilized as an efficient adsorbent for removing dacarbazine (DTIC) from wastewater. The adsorption capacity of the composite (CS/BC-MIL) was higher than both MIL-100(Fe) and the CS/BC polymeric matrix. The adsorption performance of the fabricated composite was evaluated through kinetics and isotherm studies. While isotherm studies revealed that the adsorption of DTIC onto the adsorbent can be well described by the Freundlich model, kinetics studies indicated that a combination of factors, rather than a single rate-limiting factor, are responsible for the adsorption rate. Thermodynamics investigation showed that the adsorption of DTIC to CS/BC-MIL composite is exothermic and occurs spontaneously. Additionally, due to the negative entropy change, it was established that the adsorption is governed by the enthalpy change. Exploring the solution chemistry revealed that the optimum pH for the adsorption process was about 4. Moreover, the CS/BC-MIL can selectively adsorb DTIC in the presence of other pharmaceuticals like doxorubicin (DOX). Furthermore, regeneration investigations disclosed that the composite holds its structural features and has an acceptable adsorption capacity after several cycles of adsorption/desorption.

Synthesis of innovative and sustainable gelatin@graphene oxide-crosslinked-zirconium silicate@gelatin nanobiosorbent for effective biosorption of basic fuchsin dye

Most dye stuffs and coloring materials are mainly categorized as hazardous pollutants in water effluents due to their nature as non-biodegradable, highly toxic and extremely carcinogenic. For this reason, rapid and efficient eradication of waste dyes from wastewaters before discharging into water streams must be accomplished by an acceptable approach as adsorption technique. Therefore, the present study is aimed and devoted to synthesize a novel nanobiosorbent from three different constituents, gelatin (Gel) as a sustainable natural product, graphene oxide (GO) as an example of highly stable carbonaceous material and zirconium silicate (ZrSiO₄) as an example of combined metal oxides for the formation of Gel@GO-F-ZrSiO₄@Gel by using formaldehyde (F) as a cross-linkage reagent. Several characterization techniques as FT-IR were employed to identify the incorporated surface reactive Functionalities in Gel@GO-F-ZrSiO₄@Gel as -OH, =NH, -NH₂, -COOH and C=O, etc. The morphology for particle shape and size of Gel@GO-F-ZrSiO₄@Gel were confirmed from the SEM and TEM analyses providing 15.75- 32.79 nm. The surface area was determined by the BET and found to correspond to 219.46 m² g^-1. Biosorptive removal of basic fuchsin (BF) pollutant as an example of a widely applicable dye in various activities was monitored and optimized under the influence of pH (2-10), reaction time (1-30 min), initial BF pollutant concentration (5-100 mg L^-1), nanobiosorbent dosage (5-60 mg), temperature (30-60 °C) and interfering ions. The maximum biosorptive removal values of BF dye were established as 96.0 and 95.2% using 5 and 10 mg L^-1, respectively at the recommended pH 7 condition. The Thermodynamic parameters demonstrated that the BF dye adsorption onto Gel@GO-F-ZrSiO₄@Gel was taken place via spontaneous and endothermic reaction. Chemisorption is the predominant adsorption mechanism by forming multilayers upon nonhomogeneous surface in accordance with Freundlich model hypothesis. The applicability of the optimized Gel@GO-F-ZrSiO₄@Gel in biosorptive removal of BF pollutant from real water sample was successfully accomplished by the batch technique. Thus, this study clearly shows that Gel@GO-F-ZrSiO₄@Gel exhibited significant influences on remediation of industrial effluents containing BF pollutant with superior efficiency.