前驱体溶液的pH值对锰基吸附剂脱硫性能的影响

Effect of the pH of Precursor Solution on the Desulfurization Performance of Mn-Based Sorbent

为了探究前驱体溶液的pH 值对锰基吸附剂脱硫性能的影响,以活性炭为载体,以不同pH 值硝酸锰溶液为前驱体,用亚临界水热法制备了系列吸附剂,并在固定床活性评价装置上评价了其煤气中温脱硫性能.通过X 射线衍射（XRD）、电感耦合等离子体-原子发射光谱（ICP-AES）、扫描电镜（SEM）和N2 吸附（BET）表征手段对吸附剂的活性组分存在形态、上载量以及活性炭载体的孔结构等进行相关分析.基于吸附剂脱硫活性评价和物性表征结果,发现硝酸锰前驱体溶液的pH 值对制备的吸附剂脱硫活性有较大的影响,pH 为1.53-7.31 时,值越大脱硫效果越好;当pH 值增大至8.61 时,脱硫活性降低.硝酸锰前驱体溶液的pH 值主要通过改变制备过程中锰氧化物的沉积过程影响其在活性炭载体上的负载特性,从而导致脱硫性能的不同.

A series of sorbents were prepared by subcritical-water thermal method using activated carbon as support and manganese nitrate solution as active component precursor. The performance of the prepared sorbent used in removing H2S from coal derived fuel gas was investigated in a fixed-bed reactor at mid-temperature. X-ray diffraction, inductive coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscope(SEM) and N2 adsorption(BET) were employed to analyze the structure, and the metal content and valence of the sorbent. It was found that the sulfidation activity was remarkably affected by the pH value of the precursor solution. The desulfurization activity increased with the pH of the precursor solution in the range of 1.53-7.31 and decreased when the pH was further increased up to 8.61. The loading of manganite on the activated carbon was different when the pH of the precursor solution was changed, thus the performance of the sorbent in desulfurization could be improved by adjusting the pH.