Recent progress in organic waste recycling materials for solar cell applications.

Organic waste-derived solar cells (OWSC) are a classification of third-generation photovoltaic cells in which one or more constituents are fabricated from organic waste material. They are an inspirational complement to the conventional third-generation solar cell with the potential of revolutionizing our future approach to solar cell manufacture. This article provides a study and summary of solar cells that fall under the category of OWSC. OWSC own their merit to low cost of manufacturing and environmental friendliness. This review article reveals different organic waste raw materials, preparation-to-assembly methodologies, and novel approaches to solar cell manufacturing. Ideas for the optimization of the performance of OWSC are presented. The assembly configurations and photovoltaic parameters of reported OWSC are compared in detail. An overview of the trends in the research regarding OWSC in the past decade is given. Also, the advantages and disadvantages of the different solar cell technologies are discussed, and possible trends are proposed. Industrial organic waste raw materials such as paper, coal, and plastics are among the least explored and yet most attractive for solar cell fabrication. The power conversion efficiencies for the cited works are mentioned while emphasizing the products and functions of the organic waste raw materials used.

New bimetallic adsorbent material based on cerium-iron nanoparticles highly selective and affine for arsenic(V).

Bimetallic oxy(hydroxides) have gain great interest in water treatment systems based on adsorption processes. Their high OH groups density, in addition to inheriting the oxides properties make them highly promising adsorbents of anions. In this work, highly affine and selective bimetallic oxyhydroxides of cerium and iron (Ce:Fe-P's) for arsenic(V) were synthesized by implementing an assisted microwave methodology. The Ce:Fe-P's were characterized by various techniques (SEM, FTIR, XRD and XPS) and the As(V) adsorption capacity and kinetics as well as the effect of pH and the presence of coexisting anions were determined. The results showed that Ce:Fe-P's have an outstanding As(V) adsorption capacity (179.8 mg g-1 at Ce = 3 mg L-1) even at low concentrations (120 mg g-1 at Ce = 37 µg L-1). Moreover, the adsorption equilibrium was reached very fast, just in 3 min, with an adsorption rate of 0.123 mg min-1, that is, 80% of the initial As(V) concentration of 5 mg L-1 was removed in the first 3 min. The arsenic adsorption capacity decreased only up to 20% at pH above 7, attributed to electrostatic repulsions due to the adsorbent's pHPZC, which was 6.8. On the other hand, the arsenic adsorption capacity of Ce:Fe-P's decreased just 21% in the presence of 10 mg L-1 of each of the following competing anions: F-, Cl-, SO42-, NO3-, PO43- and CO32-, which usually coincide in contaminated water with As(V). Ce:Fe-P's has proven to be one of the most promising As(V) adsorbent materials reported so far in the literature, because it presented an outstanding adsorption capacity and at the same time a very fast adsorption speed. Furthermore, the pH and the concentration of coexisting anions caused little interference in the adsorption processes. Due to the above, the Ce:Fe-P's is already in the process of intellectual protection.

Enhanced arsenic removal from water by a bimetallic material ZrOx-FeOx with high OH density.

Arsenic in groundwater for human consumption has negative effects on human's health worldwide. Due to the above, it is essential to invest in the development of new materials and more efficient technology for the elimination of such priority contaminants as arsenic. Therefore, in the present work, it was synthesized an amorphous hybrid material ZrOx-FeOx with a high density of OH groups, to improve the arsenic adsorption capacity of iron (FeOx) and zirconium (ZrOx) that makes up the bimetallic oxyhydroxide. The spectra of FT-IR and pKa's distribution suggest that in the synthesized binary oxides, a new union between the two metallic elements is formed by means of an oxygen (metal-O-metal). In addition, TEM profiles suggest that there are chemical interactions between both metals since no individual particles of iron oxide and zirconium oxide were found. According to the results, the adsorption capacity of the ZrOx-FeOx material increases 4.5 and 1.4 times with respect to FeOx and ZrOx, respectively. At pH 6, the maximum adsorption capacity was 27 mg g-1, but at pH greater than 7, the arsenic adsorption capacity onto ZrOx-FeOx decreased 66%. Graphical Abstract.

Fluoride removal in water by a hybrid adsorbent lanthanum-carbon.

Various health problems associated with drinking water containing high fluoride levels, have motivated researchers to develop more efficient adsorbents to remove fluoride from water for beneficial concentrations to human health. The objective of this research was to anchor lanthanum oxyhydroxides on a commercial granular activated carbon (GAC) to remove fluoride from water considering the effect of the solution pH, and the presence of co-existing anions and organic matter. The activated carbon was modified with lanthanum oxyhydroxides by impregnation. SEM and XRD were performed in order to determine the crystal structure and morphology of the La(III) particles anchored on the GAC surface. FT-IR and pK(a)'s distribution were determined in order to elucidate both the possible mechanism of the lanthanum anchorage on the activated carbon surface and the fluoride adsorption mechanism on the modified material. The results showed that lanthanum ions prefer binding to carboxyl and phenolic groups on the activated carbon surface. Potentiometric titrations revealed that the modified carbon (GAC-La) possesses positive charge at a pH lower than 9. The adsorption capacity of the modified GAC increased five times in contrast to an unmodified GAC adsorption capacity at an initial F(-) concentration of 20 mg L(-1). Moreover, the presence of co-existing anions had no effect on the fluoride adsorption capacity at concentrations below 30 mg L(-1), that indicated high F(-) affinity by the modified adsorbent material (GAG-La).