Bücher von H Rehana Anjum

The purpose of this work was to study the effect of chemical surface properties of activated carbons for their use in water purification. To achieve this objective, activated carbon in both granular and powdered forms namely: as received and devolatilized carbons were prepared. Proximate analysis of the carbon materials was performed. Mass titration experiments were carried out to determine the point of zero charge of the activated carbon materials. Again, using an ultraviolet spectrophotometer, the adsorption of phenol on as-received and devolatilized activated carbon was investigated. Adsorption isotherms were acquired from which the monolayer adsorption capacities were calculated.

Silver is a depleted precious resource and in the near future it all be used up. In addition to this, our country is not produced the metal at this moment. Extracting silver from enough silver containing wastes like used X-ray photographic film will considerably save the foreign currency to import this metal. The waste X-ray photographic films containing 1.5-2% (w/w) black metallic silver would be used for recovery and reuse. Around 18-20% of the world¿s silver needs are supplied by recycling photographic waste. Extraction of silver from the ore is expensive and harmful to the environment. Global demand for silver remains steadily increasing from 25,700 metric tons in 2016 to 30,500 metric tons in 2021. Most photographic and X-ray wastes contain silver thiosulphate with silver at a concentration of 5 parts per million (ppm). Several technologies exist to recover silver from X-ray photographic film such as burning the film, electrolysis, metal replacement, chemical precipitation and bacterial, enzymatic methods.