Cellulose Nanofibrils and Tubular Halloysite as Enhanced Strength Gelation Agents

A Recent Study on Remediation of Direct Blue 15 Dye Using Halloysite Nanotubes

A set of lab-scale experiments were designed and conducted to remedy Direct Blue 15 (DB15) dye using nontoxic halloysite nanotubes (HNT) with the view to be utilized in a textile industrial effluent (TIE). The DB15 adsorbed-HNT “sludge” was used as a reinforcing agent and plastic waste to fabricate the composite. To advance the knowledge and further understand the chemical phenomena associated with DB15 adsorption on HNT, different factors like pH value, adsorbate initial concentration, adsorbent dosage, and temperature on the composite were affected experimentally tested. To estimate the adsorption capacity of HNT, nine isotherm models were applied, and it was identified that the Brouers–Sotolongo adsorption isotherm model represented the best accuracy for predicting the adsorption behavior of the HNT. Likewise, the pseudo-second-order reaction was the predominant mechanism for the overall rate of the multi-step dye adsorption process. Additionally, it was demonstrated that the mass transfer during the process is diffusion-controlled, and thermodynamic assessments showed that the process is physisorption.

Adsorption Method for the Remediation of Brilliant Green Dye Using Halloysite Nanotube: Isotherm, Kinetic and Modeling Studies

The first-ever use of halloysite nanotube (HNT), a relatively low-cost nanomaterial abundantly available with minor toxicity for removing brilliant green dye from aqueous media, is reported. The factors affecting adsorption were studied by assessing the adsorption capacity, kinetics, and equilibrium thermodynamic properties. All the experiments were designed at a pH level of around 7. The Redlich-Peterson isotherm model fits best amongst the nine isotherm models studied. The kinetic studies data confirmed a pseudo model of the second order. Robotic investigations propose a rate-controlling advance being overwhelmed by intraparticle dispersion. The adsorbent features were interpreted using infrared spectroscopy and electron microscopy. Process optimization was carried out using Response Surface Methodology (RSM) through a dual section Fractional Factorial Experimental Design to contemplate the impact of boundaries on the course of adsorption. The examination of fluctuation (ANOVA) was utilized to consider the joined impact of the boundaries. The possibilities of the use of dye adsorbing HNT (“sludge”) for the fabrication of the composites using plastic waste are suggested.

Novel Terahertz Spectroscopy Technology for Crystallinity and Crystal Structure Analysis of Cellulose

Crystallinity is an essential indicator for evaluating the quality of fiber materials. Terahertz spectroscopy technology has excellent penetrability, no harmful substances, and commendable detection capability of absorption characteristics. The terahertz spectroscopy technology has great application potential in the field of fiber material research, especially for the characterization of the crystallinity of cellulose. In this work, the absorption peak of wood cellulose, microcrystalline cellulose, wood nano cellulose, and cotton nano cellulose were probed in the terahertz band to calculate the crystallinity, and the result compared with XRD and FT-IR analysis. The vibration model of cellulose molecular motion was obtained by density functional theory. The results showed that the average length of wood cellulose (WC) single fiber was 300 μm. The microcrystalline cellulose (MCC) was bar-like, and the average length was 20 μm. The cotton cellulose nanofiber (C-CNF) was a single fibrous substance with a length of 50 μm, while the wood cellulose nanofiber (W-CNF) was with a length of 250 μm. The crystallinity of cellulose samples in THz was calculated as follows: 73% for WC, 78% for MCC, 85% for W-CNF, and 90% for C-CNF. The crystallinity values were obtained by the three methods which were different to some extent. The absorption peak of the terahertz spectra was most obvious when the samples thickness was 1 mm and mixed mass ratio of the polyethylene and cellulose was 1:1. The degree of crystallinity was proportional to the terahertz absorption coefficients of cellulose, the five-movement models of cellulose molecules corresponded to the five absorption peak positions of cellulose.

Naturally derived nano- and micro-drug delivery vehicles: halloysite, vaterite and nanocellulose

We discuss prospects for halloysite nanotubes, vaterite crystals and nanocellulose to enter the market of biomaterials for drug delivery and tissue engineering, and their potential for economically viable production from abundant natural sources.