Poly(β-cyclodextrin)-Activated Carbon Gel Composites for Removal of Pesticides from Water

Pesticides are widely used in agriculture to increase and protect crop production. A substantial percentage of the active substances applied is retained in the soil or flows into water courses, constituting a very relevant environmental problem. There are several methods for the removal of pesticides from soils and water; however, their efficiency is still a challenge. An alternative to current methods relies on the use of effective adsorbents in removing pesticides which are, simultaneously, capable of releasing pesticides into the soil when needed. This reduces costs related to their application and waste treatments and, thus, overall environmental costs. In this paper, we describe the synthesis and preparation of activated carbon-containing poly(β-cyclodextrin) composites. The composites were characterized by different techniques and their ability to absorb pesticides was assessed by using two active substances: cymoxanil and imidacloprid. Composites with 5 and 10 wt% of activated carbon showed very good stability, high removal efficiencies (>75%) and pesticide sorption capacity up to ca. 50 mg g−1. The effect of additives (NaCl and urea) was also evaluated. The composites were able to release around 30% of the initial sorbed amount of pesticide without losing the capacity to keep the maximum removal efficiency in sorption/desorption cycles.

Evaluation of Topical Photo-Enhancer Assisted Intense Pulsed Light versus Methylene Blue Assisted Intense Pulsed Light for Treatment of Seborrheic Keratosis

Background seborrheic keratosis is one of the most common benign epidermal tumors that affects both sexes equally, and usually arises in individuals older than 50 years. It presents as sharply demarcated, slightly raised brownish patches or plaques, usually on sun-exposed surfaces of the skin. The clinical presentation can be quite variable and includes clinical variants, such as stucco keratosis and dermatosis papulosa nigra. Aim of the Work to evaluate the efficacy and safety of topical carbon gel photo-enhancer assisted intense pulsed light versus methylene blue assisted intense pulsed light photodynamic therapy for treatment of Seborrheic Keratosis. Patients and Methods this is a comparative prospective study that included thirty patients of skin types III to V Fitzpatrick class having multiple Seborrheic Keratosis lesions with no sex or age predilection. They were randomly recruited from Dermatology out-patient clinic of Ain –Shams University Hospitals, during period from June 2017 till March 2018. The study was approved by Research Ethical Committee of Ain Shams University and fulfilled all the ethical aspects required for human research. Results this denoted that the methylene blue-mediated photodynamic therapy (MB-PDT) (liposomal-loaded methylene blue gel 10%).and topical carbon gel photo-enhancer assisted intense pulsed light). could be effective in treating patients with Sks. Our findings denote the efficacy of them in curing multiple Sk lesions. The efficacy of methylene blue-mediated photodynamic therapy (MB-PDT) (liposomal-loaded methylene blue gel 10%). Conclusion that Intense Light Pulse using liposomal-loaded MB and Topical carbon suspension-assisted IPL treatment could be a good option for patients with indistinct pigmented or thick melanogenesic lesions. Adverse reactions to this treatment were minimal and the results acceptable, though appropriate lesions need to be chosen care- fully.

Study of the Structure and Properties of Carbon Gels from Abies Lignin and Tannins

Carbon tannin-lignin-formaldehyde (TLF) gels were obtained for the first time by carbonization of organic xerogels synthesized by sol-gel condensation of formaldehyde with polyphenolic substances isolated from abies wood and bark – ethanol lignin and condensed tannins. The effect of the mass ratio of the tannins/lignin (T/L) components in the range 1:0 – 1:2 on the specific surface areas, porous volume, apparent density, and microstructure of carbon tannin-lignin-formaldehyde gels has been studied. It was found that the density of the carbon gels increases from 0.52 to 0.60 g/cm3 with a rises in the T/L ratio from 1:0 to 1:0.2 and 1:0.5 in the initial gel and then decreases to 0.20 and 0.13 g/cm3 with an increase in the lignin content to T/L ratios of 1:1 and 1:2, respectively. The study of the porous structure of carbon gels by the BET method showed that the carbon TLF gel obtained at a T/L ratio 1:2 is characterized by the highest specific surface area (538 m2/g). Using scanning electron microscopy, the structures of TF and TLF carbon gels have been studied. It has been established that the size of globular particles has a decisive influence on the structure of gels. The size of the globule particles increases with increasing of lignin content in the composition of the tannin-lignin-formaldehyde gel that leads to the formation of a less ordered structure of the carbon gel. The porous structure of TLF carbon gels obtained from abies polyphenolic substances can be regulated by varying the ratio of tannins:lignin. The obtained carbon gels can be used as sorbents and catalyst supports

Resorcinol-Formaldehyde Carbon Gels Adsorption: A Commentary

This work is aimed at highlighting the recent progress of resorcinol-formaldehyde carbon gels adsorption of water pollutants. The synthesis strategies of the carbon gels were discussed to shed some light on the development of mesoporous matrix of carbon gel via the agglomeration of colloidal particles. The surface area of adsorbent can reach as high as 3000 m2/g by CO2 activation, while the surface functionalities are introduced through modification techniques for improving the removal performance. However, most of the recent studies are inclined at batch mode of adsorption with lack of information on the scale-up of the process in continuous mode. Carbon gel is a special class of porous material that can be moulded into desired size, hence a promising adsorbent candidate for monoliths and packings in column adsorption. Therefore, more dedicated works should be established to materialize the applications of carbon gel in column adsorption, particularly at industrial scale.

Preliminary evaluation of resorcinol-formaldehyde carbon gels for water pollutants removal

The present work was aimed to evaluate the suitability of resorcinol-formaldehyde carbon gels as adsorbent for water pollutants removal. The carbon gels were characterized using N2 adsorption-desorption isotherm for specific surface area, and Fourier transform infrared (FTIR) for surface functional groups. Methylene blue and cesium were employed as model water pollutants. Results show that the un-oxidized carbon gel, despite its lower specific surface area (333 m2/g) displayed a 118 mg/g removal of methylene blue, that is higher than 35 mg/g by the oxidized carbon gel (418 m2/g). The evaluation of adsorption kinetics revealed a lower pseudo-first order rate constant of 0.088 h-1 for 10 mg/L methylene blue adsorption. A positive effect of surface oxidation was demonstrated for cesium adsorption. On molar basis, however, the oxidized carbon gel exhibits a selective removal towards methylene blue compared to cesium. Carbon gel is a promising candidate for water pollutants removal, and further treatment needs to be sought to boost its performance.