▎ 摘　　要

NOVELTY - A magnetic chitosan lignosulfonate-graphene oxide adsorbent comprises a graphene oxide substrate, and a magnetic chitosan lignosulfonate complex grafted on the substrate. The adsorbent contains maximum amount of oxygen-containing functional groups and aromatic groups. USE - Magnetic chitosan lignosulfonate-graphene oxide adsorbent is used for removing methylene blue in wastewater (claimed) of printing industry, dyeing mill and chemical plant. ADVANTAGE - The environmentally-friendly magnetic chitosan lignosulfonate-graphene oxide adsorbent has excellent adsorption effect on methylene blue dye, and is economical and easy to separate and recycle. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (i) preparation of magnetic chitosan lignosulfonate-graphene oxide adsorbent, which involves adding 2-6 g graphite powder, 1-5 g potassium persulfate and 1-5 g phosphorus pentoxide to 8-24 mL sulfuric acid (95-98%), stirring at 70-80 degrees C for 4-5 hours in a water bath, cooling to room temperature, adding 0.3-1 L ultrapure water, stirring, washing obtained product to neutral, vacuum-drying at 50-80 degrees C, adding dried product to 80-24 mL sulfuric acid (95-98%) at 0-4 degrees C, adding 1-5 g sodium nitrate and 10-40 g potassium permanganate, stirring at 0-4 degrees C for 2-3 hours, adding 100-500 mL ultrapure water, stirring at 90-100 degrees C for 1-2 hours, adding 0.3-1 L ultrapure water and 10-40 mL hydrogen peroxide (20-40%), stirring at room temperature for 2-3 hours, adding 5-10% hydrochloric acid and ultrapure water, ultrasonically dispersing at 30-50 degrees C for 2 hours, obtaining 2-6 g/L graphene oxide, mixing 100-120 mL trivalent iron ion (0.4-0.6M) and 100-120 mL divalent iron ion (0.2-0.4M), adding 100-200 g/L sodium hydroxide at 50-60 degrees C in a water bath until the pH is 8.5-9.5, stirring for 10 minutes, heating to 60-70 degrees C, adding 0.6-0.8 mL Tween 80 (RTM: polysorbate 80), stirring for 30-50 minutes, adjusting pH to neutral, washing 3 times, ultrasonically dispersing at 30-50 degrees C for 40 minutes, obtaining 30-40 g/L magnetic fluid, adding 1-2 g chitosan to 50-100 mL acetic acid (1-2%), dissolving at 40-50 degrees C, adding 10-20 mL magnetic fluid, stirring for 30 minutes, adjusting pH to 5.5-6.5, adding 20 g/L lignosulfonate having pH of 5.5-6.5 and 5-10 mL glutaraldehyde (1-2%), reacting at 60 degrees C for 2-3 hours, obtaining reaction mixture (R1), adding mixture of 0.02-0.03 pt. wt. coconut diethanolamide and 0.05-0.06 N-hydroxysuccinimide to graphene oxide, stirring for 2-3 hours, adding obtained activated carboxyl group graphene oxide solution to reaction mixture (R1), adding 5-10 mL glutaraldehyde (1-2%), reacting at 60 degrees C for 2-3 hours, adding sodium hydroxide, adjusting pH of 8-10, washing obtained product with ultrapure water until neutral, vacuum-drying at 50-60 degrees C, grinding, and sieving with 150-mesh sieve; and # (ii) usage of magnetic chitosan lignosulfonate-graphene oxide adsorbent for removing methylene blue in wastewater.