Decontamination of Fuchsin dye by carboxymethyl cellulose-graft-poly(acrylic acid-co-itaconic acid)/carbon black nanocomposite hydrogel.

In the present work, carboxymethyl cellulose (CMC) was used to develop hydrogels as adsorbents for wastewater treatment applications due to its surface functionality and modifiable characteristics. Hydrogels (Hyd) were synthesized by grafting copolymers of acrylic acid (AA) and itaconic acid (IA) onto the CMC backbone by free radical polymerization method in order to remediate Fuchsin from aqueous solution. The presence of CMC in copolymer hydrogel of AA and IA (Poly(AA-co-IA)) up to 14.29 wt% enhances equilibrium swelling and removal efficiency. Different novel nanocomposite hydrogel samples were prepared by varying weight percentages of carbon black (CB) nanoparticles in the range of 0 to 12.5 wt%. The addition of CB up to 5 wt% enhanced the swelling and removal efficiency of the Hyd. Brunauer-Emmett-Teller (BET) test gave the surface area of 0.615, and 0.890 m2/g for Hyd and Hyd/CB, respectively, indicating that incorporation of CB led to a significant increase in Hyd surface area. The Maximum removal efficiency of Fuchsin under the optimum conditions was obtained to be 83.33, 93.54, and 98.76 % for Poly(AA-co-IA), Hyd, and Hyd/CB, respectively. The kinetic study showed that the pseudo-second-order is the best-fitted model. Isotherm studies showed that equilibrium data have a good fitness with the Langmuir model with R2 of 0.978, 0.992, and 0.982 for Poly(AA-co-IA), Hyd, and Hyd/CB, respectively. The Langmuir model gave an adsorption capacity of 26.99, 31.6, and 33.75 mg/g for Poly(AA-co-IA), Hyd, and Hyd/CB, respectively. Also, the value of n and RL parameters demonstrated that the adsorption process is physical and favorable for adsorbents. The study of thermodynamic parameters illustrated that the adsorption of Fuchsin using adsorbents is a spontaneous, exothermic, and entropy-decreasing process. Regeneration study showed that CMC-based hydrogels have higher performance in ad(de)sorption cycles than Poly(AA-co-IA) and the addition of CB to the Hyd matrix enhances reusability. Overall, Hyd and Hyd/CB can be used as promising adsorbents for the remediation of Fuchsin due to high swelling and adsorption capability.

Safranin-O cationic dye removal from wastewater using carboxymethyl cellulose-grafted-poly(acrylic acid-co-itaconic acid) nanocomposite hydrogel.

Copolymer of acrylic acid (AA) and itaconic acid (IA) grafted onto sodium carboxymethyl cellulose hydrogel (CMC-g-poly (AA-co-IA)) was successfully synthesized as an adsorbent to remove safranin-O from wastewater. The swelling and removal efficiencies of CMC-g-poly (AA-co-IA) were enhanced by increasing IA/AA molar ratio as well as by incorporation of montmorillonite clay nano-sheets (MMT). The surface area of MMT, CMC-g-poly (AA-co-IA), and CMC-g-poly (AA-co-IA) samples was 15.632, 0.61452, and 0.66584 m2/g, respectively, indicating the effectiveness of MMT nano-sheets in improving hydrogel surface area. The maximum removal efficiency of CMC-g-poly (AA-co-IA)/MMT under optimum conditions i.e., pH of 8, initial concentration of 10 mg/L, adsorbent dose of 2 g/L, and contact time of 40 min was ascertained 99.78% using a response surface methodology-central composite design (RSM-CCD). Pseudo-second-order and Langmuir models giving the maximum monolayer adsorption capacity of 18.5185 mg/g and 19.1205 mg/g for CMC-g-poly (AA-co-IA) and CMC-g-poly (AA-co-IA)/MMT samples, respectively are the best-fitted models for kinetic and equilibrium data. Thermodynamically, safranin-O decontamination was spontaneous, exothermic, and entropy decreasing. Moreover, ad (de)sorption behavior study showed that CMC-g-poly (AA-co-IA)/MMT performance was not changed after multiple recovery steps. Therefore, CMC-g-poly (AA-co-IA)/MMT was considered as a highly potential adsorbent for safranin-O removal from wastewater.

Outcome of Nonketotic Hyperglycinemia in Lebanon: 14-Year Retrospective Review.

Nonketotic hyperglycinemia is a rare inborn error of glycine metabolism characterized by a severe metabolic encephalopathy with drug-resistant seizures. Here, we report the outcome of nonketotic hyperglycinemia in a cohort of patients diagnosed and followed-up at a tertiary care reference center in Lebanon, between 2000 and 2014.Eight out of 12 patients with nonketotic hyperglycinemia were retrospectively reviewed. The remainders were excluded for incomplete data. The majority of cases presented with seizures and hypsarrhythmia or burst suppression patterns. Half of the patients died. Survival varied between 7 days and 18 years. Seizures remained unresponsive with poor outcome, despite standard supportive care and antiepileptic therapy; however, two patients were responsive to ketogenic diet and one of them became seizure-free.Scarce data on the outcome of nonketotic hyperglycinemia patients from the Middle East and North Africa region are available. The ketogenic diet, in combination with standard therapies, appears to be effective in controlling the seizures in this devastating disorder. Larger multicenter studies are still needed to establish the role of the ketogenic diet in nonketotic hyperglycinemia.

Review on recent progress in chitosan-based hydrogels for wastewater treatment application.

Recently, chitosan has been used as a raw material for synthesis of hydrogels in a wide range of potential and practical applications like wastewater treatment, drug delivery, and tissue engineering. This review represents an overview of the application of chitosan-based hydrogels for wastewater treatment and helps researchers to better understand the potential of these adsorbents for wastewater treatment. It covers recently used and prospected methods for synthesis and modification of these hydrogels. Chitosan-based hydrogels are modified physically and chemically through crosslinking, grafting, impregnation, incorporating of hard fillers, blending, interpenetrating, and ion-imprinting methods to improve adsorption and mechanical properties. Understanding of these methods provides useful information in the design of efficient chitosan-based hydrogels and the select of appropriate pollutants for removal. This review provides a brief outlook on future prospects of chitosan-based hydrogels for wastewater application.

A review on acrylic based hydrogels and their applications in wastewater treatment.

The acrylic based hydrogels have attracted the attention of many researchers in the field of pollutants adsorption such as dyes and metal cations due to their high swelling and adsorption capacities. This review introduces acrylic based hydrogels and focuses on their adsorption properties. We first described the methods for synthesizing hydrogels. Usual methods of characterization of acrylic based hydrogels such as swelling, adsorption capacity and desorption efficiency of the pollutants have been investigated. In addition, the adsorption isotherm and kinetic models which determine the mechanism of pollutants' adsorption by hydrogels have been introduced and relations that determine the values of thermodynamic parameters which define accomplishment of adsorption process have been investigated. In the following sections, a perfect insight has been provided on natural and synthetic acrylic based hydrogels. The effective parameters of swelling and adsorption by acrylic based hydrogels have been reviewed and the mechanism of pollutant's adsorption by acrylic based hydrogels has been discussed.