1种蟹副产物来源的生物炭的制备、表征和应用

Preparation,characterization and application of a biochar from crab by-product

中华绒螯蟹(Eriocheir sinensis)的高消费量造成了大量蟹副产物的产生,生物炭作为一种低成本新型环保材料,可以作为蟹废弃生物质综合开发的重要方向。实验以蟹副产品酶解提取蛋白后的剩余固体物为研究对象,采用氮气吸附法(BET)测定制备生物炭的比表面积,确定蟹副产品生物炭制备的最佳温度条件;利用元素分析仪和国标法,测定最佳条件下制备生物炭的主要元素含量和其对Cu^2+、Cd^2+和Pb^2+的吸附能力;利用傅里叶红外光谱(FT-IR)和扫描电镜(SEM)对生物炭的结构和表面形态进行分析,探讨生物炭的吸附机制。结果表明:1)500℃下制备的生物炭具有最大比表面积3.9963 m^2/g和最高产率62.60%,比表面积相比于原料增加63.12%,确定500℃为生物炭制备的最佳温度。2)500℃制备生物炭的固碳能力一般,对于Cu^2+、Cd^2+和Pb^2+的吸附率分别为100.00%、96.67%和90.60%。3)FT-IR结果显示,与原料相比,500℃制备生物炭有芳环结构形成、脂肪族类物质减少、芳香族—CC—结构减少、芳香族羰基/羧基—CO形成和羟基官能团部分残留。SEM扫描结果显示,生物炭的外观疏松多孔,纤维结构和层状结构明显。生物炭对Cu^2+、Cd^2+和Pb^2+作用机理分别为离子吸附、溶解-沉淀和π电子吸附及溶解-沉淀和化学吸附。上述结果说明,利用蟹副产品提取蛋白后的剩余固体物制备而成的生物炭对铜、镉和铅3种重金属离子具有良好的吸附能力,可用于水的净化处理。研究成果可为蟹副产物的高值化开发利用提供思路,有助于推动低污染、低成本的蟹副产品生物炭的工厂化应用。

The high consumption of Chinese mitten crab(Eriocheir sinensis)resulted in a large quantity of crab by-products production.Biochar,as a new type of new environmental-friendly material,can be an important direction for the comprehensive development for crab by-products.Firstly,the left solid residues,produced after protein extraction via enzymatic hydrolysis from Chinese mitten crab by-products,were used to make biochar under different high temperature conditions.The specific surface area of biochar,as the screening indicator,was determined by nitrogen adsorption method(BET).The elements analysis of biochar was conducted by the elemental analyzer.BET results showed that the biochar prepared at 500℃had the largest specific surface area of 3.9963m^2/g,which increased by 63.12%more than the raw material,and a highest yield of 62.60%and an average carbon sequestration capacity.Then the biochar prepared at 500℃was used for the follow-up experiments.The adsorption experiments of biochar was performed for three heavy metal ions of Cu^2+,Cd^2+and Pb^2+,and the structure and surface morphology of biochar were analyzed by FT-IR(Fourier transform infrared spectroscopy)and SEM(scanning electron microscopy)in order to explore the adsorption mechanism of biochar.The biochar prepared at 500℃had an adsorption rate of 100.00%,96.67%and 90.60%for Cu^2+,Cd^2+and Pb^2+,respectively.FT-IR results showed that the biochar led to the formation of aromatic ring structure of biochar,the reduction of aliphatics and aromatic-C=C-structure,the formation of aromatic carbonyl/carboxyl-C=O and the residual of hydroxyl functional groups.SEM results showed that the biochar was loose and porous,and has obvious fiber structure and layer structure.The results of adsorption experiments demonstrated that the adsorption mechanisms of biochar for Cu^2+,Cd^2+,and Pb^2+were by ion adsorption,dissolution-precipitation andπ-electron adsorption,and dissolution-precipitation,respectively.The study not only exhibited a good adsorption capacity of biochar for copper,cadmium and lead,which could be further utilized to the water treatment,but also provided ideas for the high-value utilization of crab by-products help to push its industrialization forward.