IP Library › Granted Patent US 12685994
Granted Patent B2
US 12685994 · App. 19/375,340 · Granted Jul 21, 2026

Water purification method using biochar layered double hydroxide composite

Inventor: Mukarram Zubair (Dammam, SA)
Assignee: Imam Abdulrahman Bin Faisal University
B01J20/06B01J20/20B01J20/24B01J20/28007B01J20/28019B01J20/2803B01J20/28061B01J20/28083B01J20/3078B01J20/3212B01J20/3214B01J20/3236B01J20/324B01J20/3293C02F1/288C02F1/281C02F1/283C02F1/286C02F2101/308C02F2305/08
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Quick Facts
Patent No.
US 12685994
App. No.
19/375,340
Granted
Jul 21, 2026
Kind
B2
Abstract

A method of adsorbing a dye from an aqueous solution including contacting a composition with the aqueous solution. At least a portion of the dye adsorbs to the composition. The composition includes biochar, cellulose nanocrystals, and a layered double hydroxide (LDH). The LDH includes Cu and Fe. Particles of the LDH and the biochar at least partially cover an outer surface of the cellulose nanocrystals.

Claims (27)

1 . A water purification method, comprising:

contacting a composition with an aqueous solution comprising a dye,

wherein at least a portion of the dye adsorbs to the composition during the contacting,

wherein the composition comprises:

biochar;

cellulose nanocrystals; and

a layered double hydroxide (LDH),

wherein the LDH comprises Cu and Fe,

wherein particles of the LDH and the biochar completely envelop the cellulose nanocrystals; and

wherein the composition comprises from 1-30 wt. % of the cellulose nanocrystals based on the weight of the biochar in the composition.

2 . The method of claim 1 , wherein the composition comprises 0.1-9 wt. % of the cellulose nanocrystals, 10-30 wt. % of the biochar, and 65-75 wt. % of the LDH, based on a total weight of the composition.

3 . The method of claim 1 , wherein the LDH comprises Cu and Fe in a ratio range of 10:1 to 1:1.

4 . The method of claim 1 , wherein particles of the LDH are spherical and have an average diameter of 10-30 nm.

5 . The method of claim 1 , wherein particles of the cellulose nanocrystals have a rod shape with an average length of 300-900 nanometers (nm), and an average thickness of 10-50 nm.

6 . The method of claim 1 , wherein the particles of the cellulose nanocrystals form aggregates, wherein the aggregates have an average thickness of 100 to 500 nm.

7 . The method of claim 1 , wherein the LDH is uniformly distributed on the outer surface of the cellulose nanocrystals.

8 . The method of claim 1 , wherein the composition is porous, and has an average pore size of 15-20 nm.

9 . The method of claim 1 , wherein the composition has —OH 2 +on an outer surface.

10 . The method of claim 1 , wherein the composition has a Brunauer-Emmett-Teller (BET) surface area of 200-280 meter square per gram (m 2 /g).

11 . The method of claim 1 , wherein the aqueous solution has a pH of 2-5.

12 . The method of claim 1 , wherein the aqueous solution has a temperature of 24-30° C.

13 . The method of claim 1 , wherein the composition has a concentration of 1-10 milligrams per liter (mg/L) in the aqueous solution.

14 . The method of claim 1 , wherein the dye has a concentration of 40-200 mg/L in the aqueous solution.

15 . The method of claim 1 , wherein the adsorbing of the dye to the composition reaches an equilibrium in 30-45 minutes.

16 . The method of claim 1 , wherein the adsorbing of the dye to the composition is through hydrogen bonding and metal complexation with the Cu and Fe.

17 . The method of claim 1 , wherein the dye is an azo dye.

18 . The method of claim 1 , wherein the maximum adsorption capacity of the composition is 600-900 milligrams per gram (mg/g).