Study On Water Quality Characteristics And Technology Of Kelp Culture In Ulungu Lake,xinjiang

Kelp farming has become a public focus due to the advantages of low price,wide sources,fast reproduction,high yield and renewable nature,but the expansion of nearshore aquaculture in the last five years,limited space in maritime farming areas and increased farming density have led to a decline in the seawater.Water quality indicators（e.g.salinity,Na⁺,K⁺,etc.）in Ulungu Lake are close to those of kelp farming water,making kelp farming in Ulungu Lake feasible,which provides ideas for saltwater lake renovation.However,the SO₄^2-concentration in the lake water（C=6600 mg/L）was much higher than that of seawater（C=1571 mg/L）,so a biomass carbon adsorbent（KPC）for efficient SO₄^2-removal was prepared from waste kelp trimmings by the calcium chloride activation-carbonation method and tested by characterization means（SEM,FTIR,XPS,etc.）,and the lake water after SO₄^2-abatement was subsequently used for kelp nursery research,and the following conclusions were obtained:The main hydrochemical type of surface water in the study area was Cl^--SO₄^2--Na⁺.The concentration of SO₄^2-in most samples was higher than the drinking water and seawater standards,with salinity values as high as 2 g/L and maximum SO₄^2-concentrations as high as 6600 mg/L.The lake water was brackish.Due to the special characteristics of the water chemistry in the lake,the factor of high sulphate has become a focus of concern affecting the growth of kelp.The adsorbent was characterised by transmission electron microscopy（TEM-EDS）,X-ray photoelectron spectroscopy（XPS）and specific surface testing（BET）,the results showed that Ca²⁺was present on the surface of KPC,which had a porous structure and a larger specific surface area than the unactivated kelp-based activated carbon material.the pore structure of the KPC surface was predominantly mesoporous with an Specific surface srea（SSA）of 254.675 m²/g.the waste kelp-based activated carbon adsorbent material showed good affinity for SO₄^2-with a maximum SO₄^2-adsorption capacity of 866.98mg/g,much higher than other materials such as grapefruit peel（adsorption capacity of 35.21 mg/g）and coconut shell（adsorption capacity of 4.90 mg/g）.Kinetic studies showed that the adsorption of SO₄^2-by simulated water and Ulungu Lake water followed quasi-secondary kinetics.Analysis of the isotherm data indicated that the Langmuir isotherm model was consistent with SO₄^2-in the simulated water.In dynamic adsorption experiments,The experimental results showed that penetration times were 10min,16 min and 27 min for column heights ranging from 5.0 cm to 10.0 cm,with depletion times of 180min,300 min and 420 min,respectively.The penetration times were 10 min,8 min and 6 min for sulphate ion concentrations from 300 mg/L to 500 mg/L,and the depletion times were 236 min,200 min and 167min,respectively.Based on the water quality characteristics of Ulungu Lake and the results of the SO₄^2-removal study by KPC,the modified lake water was used for kelp seedling nursery and kelp sporulation studies after adjusting the level of SO₄^2-in the lake water.All other treatment conditions being equal,the survival time of the modified lake water seedlings was significantly increased by 7 days compared to the original lake water seedlings.The germination rate was 81.82%after attachment of normal seawater kelp swimming spores and 77.44%after the modified lake water treatment.