Patent ID: 7442232

Claim:
An adsorbent comprising an alkali metal promoted, mixed trivalent layered double hydroxide (LDH) composition, wherein the mixed trivalent layered double hydroxide (LDH) composition is heated to a temperature ranging from about 300° C. to 450° C. to provide the adsorbent, and wherein the alkali metal promoted, mixed trivalent metal LDH composition has the following general formula: [M1 1−x (M2 y M3 (1−y) ) x(OH) 2 (A) x/2 .z H 2 O].v [M4 w CO 3 ] wherein the subscript “x” is a number between 0 and 1; the subscript “y” is a number ranging from greater than 0 to about 0.05; “z” is a number ranging from 0 to about 8; the subscript “w” is the integer 1 or 2, wherein when “w” is the integer 1 the CO 3 becomes HCO 3 ; “v” is a number ranging from 0 to about 0.01; “M1” is a divalent metal selected from magnesium (Mg), calcium (Ca), strontium (Sr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn); “M2” and “M3” are each a trivalent metal selected from aluminum (Al), chromium (Cr), Mn, Fe, Co, lanthanum (La), cerium (Ce), galium (Ga), indium (In), the lanthanide series of metals, and mixtures thereof; “A” is an anion selected from CO 3 , SO 4 , and HPO 4 ; and “M4” is an alkali metal selected from sodium (Na), potassium (K), robidium (Rb), cesium (Cs), and lithium (Li).