Biochar shows great promise for use in adsorbing pollutants. However, a process for enhancing its adsorption capacity and re-collection efficiency is yet to be further developed. Hence, in this study, we developed a type of biochar coated with magnetic Fe3O4 nanoparticles (i.e., magnetic biochar (MBC)) and assessed its use for crystal violet (CV) adsorption as well as its recycling potential. The coating of Fe3O4 nanoparticles, which was not only on the surface, but also in the interior of biochar, performed two functions. Firstly, it produced a saturation magnetization of 61.48 emu/g, which enabled the biochar being efficiently re-collected using a magnet. Secondly, it significantly enhanced the adsorption capacity of the biochar (from 80.36 to 99.19 mg/g). The adsorption capacity of the MBC was determined to be the largest by so far (349.40 mg/g) for an initial CV concentration of 400 mg/L, pH of 6.0 and temperature of 40 °C and the adsorption capacity of re-collected MBC was 73.31 mg/g. The adsorption of CV by the MBC was found to be a spontaneous and endothermic physical process in which the intraparticle diffusion was the limiting step. These findings inspire us to use other similar materials to tackle the menace of pollutions.

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Efficient removal of crystal violet using Fe3O4-coated biochar: the role of the Fe3O4 nanoparticles and modeling study their adsorption behavior.

A novel cellulose-based adsorbent (CGS) was synthesized by a facile, two-step modification route. It was characterized by the FTIR, XRD, and SEM technique. The adsorption characteristics of CGS were compared with those of native cellulose using crystal violet (CV) as an adsorbate in this work. The effects of contact time, temperature, pH, and initial concentration on the sorption were all investigated. The adsorption kinetics for both CGS and cellulose were found to follow a pseudo-second-order (P-S-O) kinetic model. The equilibrium data of CGS fitted well with the Langmuir isothermal model, and the maximum theoretical adsorption capacity of CGS for CV was 218.82 mg g–1 at 50 °C; the adsorption increased by 70.8% compared to that of native cellulose. A thermodynamics study was also performed. The comparative study confirmed that the structure of CGS is more conducive for the adsorption of CV than cellulose. Furthermore, adsorption/desorption experiments showed that CGS could be reused for at least eight c...

Removal of Crystal Violet by a Novel Cellulose-Based Adsorbent: Comparison with Native Cellulose

Microwave–ultrasound-assisted facile synthesis of a dumbbell- and flower-shaped potato starch phosphate (PSP) polymer, hereafter PSP, was carried out by cross-linking the hydroxyl groups of native ...

Enhanced and Selective Adsorption of Zn(II), Pb(II), Cd(II), and Hg(II) Ions by a Dumbbell- and Flower-Shaped Potato Starch Phosphate Polymer: A Combined Experimental and DFT Calculation Study.

The capability of multiple valued logic (MVL) circuits to achieve higher storage density when compared to that of existing binary circuits is highly impressive. Recently, MVL circuits have attracted significant attention for the design of digital systems. Carbon nanotube field effect transistors (CNTFETs) have shown great promise for design of MVL based circuits, due to the fact that the scalable threshold voltage of CNTFETs can be utilized easily for the multiple voltage designs. In addition, resistive random access memory (RRAM) is also a feasible option for the design of MVL circuits, owing to its multilevel cell capability that enables the storage of multiple resistance states within a single cell. In this manuscript, a design approach for ternary combinational logic circuits while using CNTFETs and RRAM is presented. The designs of ternary half adder, ternary half subtractor, ternary full adder, and ternary full subtractor are evaluated while using Synopsis HSPICE simulation software with standard 32 nm CNTFET technology under different operating conditions, including different supply voltages, output load variation, and different operating temperatures. Finally, the proposed designs are compared with the state-of-the-art ternary designs. Based on the obtained simulation results, the proposed designs show a significant reduction in the transistor count, decreased cell area, and lower power consumption. In addition, due to the participation of RRAM, the proposed designs have advantages in terms of non-volatility.

https://www.mdpi.com/2079-9292/10/1/79/pdf

Syed Zeeshan Fatima

Papers

Preparation and characterization of 5-sulphosalicylic acid doped tetraethoxysilane composite ion-exchange material by sol-gel method.

Carbon nanotube field effect transistor (CNTFET) operational transconductance amplifier (OTA) based design of high frequency memristor emulator