Sorption And Desorption Mechanism Of Calcium Mud And Magnesium Mud And Their Different Treated Soil To Phosphorus And Heavy Metals

A isothermal adsorption-desorption experiment was conducted to study the adsorption difference of two fertilizer industrial wastes-calcium mud and magnesium mud and soil to exogenous P and heavy metals Cu, Zn, and Pb. Then the effect of calcium mud, magnesium mud, weathered coal, chemical fertilizer and their mixture on the adsoortion-desorption of soil to P、heavy metals Cu、 Zn、Pb was studied. The results showed that:1. The maximum P adsorption capacities of calcium mud、magnesium mud、and soil were 37.45 mg/g, 30.49 mg/g, and 14.43 mg/g respectively.The maximum P adsorption capacity of the treatment of organic ferlitizer and magnesium mud was 48.08 mg/g and was 244.91% higher than that of treatment CK (13.94mg/g). The maximum P adsorption capacity of other treatments was:treatment of organic-inorganic fertilizer and magnesium mud (21.51mg/g)> treatment of calcium mud (20.79mg/g)> treatment of inorganic fertilizer and calcium mud (20.75 mg/g)> treatment of inorganic fertilizer and magnesium mud (19.49 mg/g)> treatment of organic-inorganic fertilizer and calcium mud (18.94 mg/g)> treatment of weathered coal and calcium mud (18.21 mg/g)> treatment of magnesium mud (18.18 mg/g)> treatment of inorganic fertilizer and magnesium mud (17.57 mg/g)> treatment of weathered coal and magnesium mud (16.00 mg/g). They increased 54.30%,49.14%,48.85%,39.81%,35.87%,30.63%,30.41%,26.04%, 14.78% than CK respectively. The effect of treatments applied with calcium mud was better than that of treatments applied with magnesium mud.The desorption rate of P in treatments of calcium mud or magnesium mud mixed with organic chemical fertilizer or inorganic chemical fertilizer was higher than that in treatments of only calcium mud, magnesium mud, organic chemical fertilizer, or inorganic chemical fertilizer. The desorption rate of P in the treatment of calcium mud, organic chemical fertilizer, and inorganic chemical fertilizer was the highest.2. The maximum Zn2+ adsorption capacity of calcium mud, magnesium mud, and soil was 33.00 mg/g, 30.67 mg/g, and 9.96 mg/g respectively. The maximum Zn2+ adsorbing capacity (Qm) in the treatment of organic and inorganic chemical fertilizer and calcium mud was 13.25 mg/g and was 65.50% higher than that in treatment CK (8.006 mg/g). The maximum Zn2+ adsorbing capacity of other treatments was: treatment of weathered coal and calcium mud (12.39 mg/g)> treatment of organic fertilizer and magnesium mud (11.79 mg/g)> treatment of organic fertilizer and calcium mud (10.57 mg/g)> treatment of weathered coal and magnesium ud (10.56 mg/g)> treatment of inorganic fertilizer and magnesium mud (10.08 mg/g) > treatment of calcium mud (9.93 mg/g)> treatment of organic-inorganic fertilizer and magnesium mud (9.82 mg/g)> treatment of magnesium mud (9.22 mg/g)> treatment of inorganic fertilizer and calcium mud (8.58 mg/g) and increased 54.76%,47.26%,32.03%,31.90%,25.91%,24.03%,22.66%,15.16%, 7.17% than that in treatment CK. The effect of treatments applied with calcium mud was better than treatments applied with magnesium mud.The desorption rate of Zn+ in all treatments increased as the adsorbtion capacity of Zn2+ increased. The desorption rate of Zn was the highest in the treatment of inorganic fertilizer and calcium mud.3、The maximum Pb2+ adsorption capacity of calcium mud, magnesium mud, and soil was 32.57 mg/g, 28.90 mg/g, and 12.00 mg/g respectively. The maximum Pb+ adsorption capacity was was 22.32 mg/g in the treatment of organic and inorganic fertilizer and calcium mud and was 119.25% higher than that in the treatment CK (10.18mg/g). The other treatments were that treatment of organic fertilizer and magnesium mud (21.98 mg/g)> treatment of weathered coal and calcium mud (21.17 mg/g)> treatment of inorganic fertilizer and calcium mud (20.12 mg/g)> treatment of organic and inorganic fertilizer and magnesium mud (15.02 mg/g)> treatment of magnesium mud (14.90 mg/g)> treatment of calcium mud (14.32 mg/g)> treatment of weathered coal and calcium mud (11.29 mg/g)> treatment of inorganic fertilizer and magnesium mud (11.09 mg/g) and increased 109.95%,97.64%,47.54%,46.37%,40.67%,10.90%,8.94% than treatment CK respectively. It showed that different fertilization treatments all increased the adsorption ability of soil.to Pb2+.The desorption rate of Pb in different fertilization treatments was all under 1%. The desorption rate of Pb in the treatment of organic fertilizer and calcium mud was the highest.The showed that most adsorbed Pb2+ could not be desorptioned in soil.4、The maximum Cu2+ adsorption capacity of calcium mud, magnesium mud, and soil was 35.84 mg/g,32.89 mg/g, and 14.73 mg/g respectively. The maximum adsorption capacity of Cu2+ in the treatment of organic and inorganic fertilizer and calcium mud was 24.10 mg/g and was 264.59% higher than that in treatment CK (6.61 mg/g).The other treatments were that treatment of organic fertilizer and calcium mud (9.31 mg/g)> treatment of weathered coal and calcium mud (10.92 mg/g)> treatment of organic and inorganic fertilizer and magnesium mud (10.15 mg/g)> treatment of inorganic fertilizer and calcium mud (10.10 mg/g)> treatment of organic fertilizer and magnesium mud (8.63 mg/g)> treatment of calcium mud (8.50 mg/g)> treatment of inorganic fertilizer and magnesium mud (8.01 mg/g)> treatment of weathered coal and magnesium mud (7.52 mg/g)> treatment of magnesium mud (7.27 mg/g) and increased 92.31%,65.20%,54.16%,52.79%,30.56%,28.59%,21.18%,13.77%,9.98% than treatment CK respectively. The maximum adsorption capacity of Cu2+ in the treatments with organic fertilizer was greater than that in the treatments without organic fertilizer and application of experimental materials increased the adsorption capacity of soil to Cu2+.The desorption rate of Cu2+ in treatment CK was the highest. It showed that fertilization increased the adsorption ability of soil to Cu2+ and the adsorption capacity of Cu2+ in treatments with organic matter was higher.