1 : A method of removing an organic pollutant from water, comprising: contacting the water with a ball milled and sonicated oil fly ash powder to adsorb the organic pollutant onto the ball milled and sonicated oil fly ash powder; wherein the ball milled and sonicated oil fly ash powder has an average particle size of less than less than 1 μm.
2 : The method of claim 1 , wherein the ball milled and sonicated oil fly ash powder is contacted with the water for 5-60 min.
3 : The method of claim 1 , wherein the ball milled and sonicated oil fly ash powder has a carbon content of greater than 65 wt. %, based on a total weight of the ball milled and sonicated oil fly ash powder.
4 : The method of claim 1 , wherein the ball milled and sonicated oil fly ash powder has a SiO 2 content of less than 3 wt. %, and a Al 2 O 3 content of less than 3 wt. %, each based on a total weight of the ball milled and sonicated oil fly ash powder.
5 : The method of claim 1 , wherein the ball milled and sonicated oil fly ash powder has a bimodal particle size distribution with nanoparticles having an average particle size of 10-100 nm, and sub-micron sized particles having an average particle size of 0.2-0.9 μm.
6 : The method of claim 1 , wherein 0.01-0.5 g of the ball milled and sonicated oil fly ash powder is employed per L of the water during the contacting.
7 : The method of claim 1 , wherein the organic pollutant is at least one selected from the group consisting of methylene blue, Congo red, brilliant green, and crystal violet.
8 : The method of claim 1 , wherein at least 75% of the organic pollutant is removed from the water relative to an initial concentration.
9 : A method of producing a ball milled and sonicated oil fly ash powder, comprising: ball milling oil fly ash to provide ball milled oil fly ash particles with an average particle size of less than 1 μm; sonicating the ball milled oil fly ash particles in an aqueous medium to form a mixture comprising ball milled and sonicated oil fly ash particles and a supernatant; and separating the ball milled and sonicated oil fly ash particles from the supernatant and drying to form the ball milled and sonicated oil fly ash powder.
10 : The method of claim 9 , wherein the oil fly ash has a carbon content of greater than 65 wt. %, based on a total weight of the oil fly ash.
11 : The method of claim 9 , wherein the oil fly ash has a SiO 2 content of less than 3 wt. %, and a Al 2 O 3 content of less than 3 wt. %, each based on a total weight of the oil fly ash.
12 : The method of claim 9 , wherein the oil fly ash has a vanadium content of 1,000-70,000 ppm, and a nickel content of 500-15,000 ppm.
13 : The method of claim 9 , wherein the ball milled and sonicated oil fly ash powder has an average particle size of less than less than 1 μm.
14 : The method of claim 13 , wherein the ball milled and sonicated oil fly ash powder has a bimodal particle size distribution with nanoparticles having an average particle size of 10-100 nm, and sub-micron sized particles having an average particle size of 0.2-0.9 μm.
15 : The method of claim 9 , wherein the oil fly ash is ball milled in a high energy ball mill at a rotational speed of 100 to 400 rpm.
16 : The method of claim 9 , wherein the oil fly ash is ball milled in tungsten carbide vials with tungsten carbide or stainless steel balls, and with a ball to oil fly ash weight ratio of from 8:1 to 12:1.
17 : The method of claim 9 , wherein the oil fly ash particles are ball milled for 5-11 hours and sonicated for at least 1 hour.
18 : The method of claim 9 , further comprising shaking and/or stirring the mixture for at least 30 min. after sonicating.
19 : A method of collecting vanadium and nickel metal species from oil fly ash, the method comprising: ball milling the oil fly ash to provide ball milled oil fly ash particles with an average particle size of less than 1 μm; sonicating the ball milled oil fly ash particles in an aqueous medium to form a mixture comprising ball milled and sonicated oil fly ash particles and a supernatant; separating the ball milled and sonicated oil fly ash particles from the supernatant and collecting the supernatant; and collecting the vanadium and nickel metal species from the supernatant by a crystal bar process, a precipitation process, or a solvent extraction process.
20 : The method of claim 19 , wherein the oil fly ash has a vanadium content of 1,000-70,000 ppm and a nickel content of 500-15,000 ppm, and the method provides 20-50% more vanadium and 40-80% more nickel compared to a process employing oil fly ash which is shaken and/or stirred in the aqueous medium but has not been ball milled or sonicated.
