污泥与生物质共热解制备生物质炭工艺优化及吸附性能

通过污泥与秸秆（玉米秸秆、水稻秸秆、小麦秸秆、芝麻秸秆）慢速共热解的方法，在不同热解温度（300℃、400℃、500℃、600℃）、热解时间（0.5h、1h、1.5h、2h）及配比（污泥与生物质1∶0、1∶0.5、1∶1、1∶2）条件下制备4种生物质炭，即SCBC（污泥-玉米秸秆生物质炭）、SRBC（污泥-水稻秸秆生物质炭）、SWBC（污泥-小麦生物质炭）、SSBC（污泥-芝麻生物质炭），研究了不同热解条件对生物质炭产率、pH、元素组成、表面特征、吸附性能的影响，并根据吸附性能筛选出各生物质炭的最优制备工艺。结果表明，热解温度为500℃、热解时间为2h、污泥与玉米秸秆、芝麻秸秆配比为1∶1时，污泥与水稻秸秆、小麦秸秆配比为1∶2时，制备的生物质炭吸附性能最优。最优制备工艺条件下，4种生物质炭吸附性能相比：SWBC > SRBC > SCBC > SSBC。

Process optimization and adsorption performance of biochars prepared by co-pyrolysis of sludge and biomasses

Biochars were produced by slow co-pyrolysis of sewage sludge and straws (corn straw, rice straw, wheat straw, sesame straw) at different pyrolysis temperatures (300℃, 400℃, 500℃, 600℃), pyrolysis times (0.5h, 1h, 1.5h, 2h) and ratios (sludge/biomass 1:0, 1:0.5, 1:1, 1:2). The four types of biochars were labelled SCBC (biochar derived from sludge and corn straw), SRBC (biochar derived from sludge and rice straw), SWBC (biochar derived from sludge and wheat straw), SSBC (biochar derived from sludge and sesame biomass), respectively. The effect of different pyrolysis temperatures, times, and ratios on pH, yields, ash contents, pore characteristics, and adsorption capacity was studied. Based on the adsorption properties, the optimum production process of biochar was determined. The results showed that when the pyrolysis temperature was 500℃, the pyrolysis time was 2h, the ratio of sludge to corn straw and sesame straw was 1:1, the ratio of sludge to rice straw and wheat straw was 1:2, the adsorption performance of biochar was the best. Under the optimum preparation conditions, the adsorption properties of four kinds of biochars followed the order:SWBC > SRBC > SCBC > SSBC. This study provides technical support for the utilization of sewage sludge and straws.