Novel 3D lightweight carbon foam as an effective adsorbent for arsenic(V) removal from contaminated water

In the present work, an efficient system for removal of pentavalent arsenic (As(V)) from water has been developed using a novel three-dimensional (3D) lightweight carbon foam. The carbon foam was synthesized from phenolic resin by a sacrificial template technique followed by stabilisation and carbonisation. The carbon foam was characterized by X-ray diffraction (XRD) for phase identification and energy dispersive spectroscopy (EDS) for compositional analysis. This same carbon foam has been utilized for the removal of As(V), and remaining concentrations were determined using an atomic absorption spectrophotometer-hydride generator (AAS-HG) at varying adsorption parameters, viz. time, pH and adsorbate dose. The adsorption data is best fitted to a Langmuir isotherm and suggests monolayer adsorption over a homogenous surface. The adsorption capacity of carbon foam is 38.4 mu g g(-1) and the % of arsenic removal is 99.1%, which is very high as compared to other low density carbon materials. The carbon foams efficiently adsorbed As(V) and purify water below the prescribed limits of the world health organization (WHO) and the United States-environmental protection agency (US-EPA)

Zinc peroxide nanomaterial as an adsorbent for removal of Congo red dye from waste water

In the past decade, various natural byproducts, advanced metal oxide composites and photocatalysts have been reported for removal of dyes from water. Although these materials are useful for select applications, they have some limitations such as use at fixed temperature, ultra violet (UV) light and the need for sophisticated experimental set up. These materials can remove dyes up to a certain extent but require long time. To overcome these limitations, a promising adsorbent zinc peroxide (ZnO2) nanomaterial has been developed for the removal of Congo red (CR) dye from contaminated water. ZnO2 is highly efficient even in the absence of sunlight to remove CR from contaminated water upto the permissible limits set by the World Health Organization (WHO) and the United States- Environmental Protection Agency (US-EPA). The adsorbent has a specific property to adjust the pH of the test solution within 6.5-7.5 range irrespective of acidic or basic nature of water. The adsorption capacity of the material for CR dye was 208 mg g(-1) within 10 min at 2-10 pH range. The proposed material could be useful for the industries involved in water purification. The removal of CR has been confirmed by spectroscopic and microscopic techniques. The adsorption data followed a second order kinetics and Freundlich isotherm

Study of cyanide removal from contaminated water using zinc peroxide nanomaterial

The present study highlights the potential application of zinc peroxide (ZnO2) nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO2 synthesis has been granted in United States of America (US Patent number 8,715,612; May 2014), South Africa, Bangladesh, and India. The ZnO2 nanomaterial was capped with polyvinylpyrrolidone (PVP) to control the particle size. The PVP capped Zn02 nanomaterial (PVP-Zn02) before and after adsorption of cyanide was characterized by scanning electron microscope, transmission electron microscope, X-ray diffractometer, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrometry. The remaining concentration of cyanide after adsorption by PVP-ZnO2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO2 was also studied as a function of pH, adsorbent dose, time and concentration of cyanide. The maximum removal of cyanide was observed in pH range 5.8-7.8 within 15 min. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics