Preparation Of Sewage Sludge Ramification Adsorbents And Its Application In Adsorption Of Lead, Copper And Sulfur Dioxide

In resent years, the quantity and the scale of municipal wastewater treatment plants in both domestic and aboard are increasing rapidly. During the disposal of wastewater, large amounts of sludge are produced; furthermore, the process of storage, treatment as well as disposal of sludge may pollute the nature environment, which becomes one of the social and environmental problems throughout the world. This paper proposes a useful method to utilize the excessive sludge to make up effective adsorbent for adsorbing poisonous substances such as heavy metals in wastewater and sulfur dioxide in polluted atmosphere.The main subject of this paper is to study the making condition and the making process of the sludge ramification adsorbent. The optimum condition is found by the method combining orthogonal experiment with single-factor ones, and the capability of the adsorbent is measured with certain physical and chemical methods. This adsorbent is used to adsorb Pb2+and Cu2+ in simulated wastewater as well as sulfur dioxide in simulated flue gas, and the influencing factors of the removal efficiency and adsorption capacity to sulfur dioxide as well as the adsorption mechanism are also studied.The experiment results show that at certain rising-rate of the temperature, the process of sludge pyrolysis can be divided into 3 stages, and the phrolysis mechanism of each stage fits to certain pyrolysis model. The dimension distribution of the aperture on the surface of the adsorbent belongs to micropore and mesopore, varying from 0.1 to 0.4 um. The physical and chemical characteristic of the surface of adsorbent are as follows: real density 2.8 g/cm , inspective density 0.54 g/cm , special surface area 298m2/g, special porosity 0.729 g/cm3, hole ratio 0.807, microporosity 0.528 g/cm3.The sludge ramification adsorbent has perfect effect on removing heavy metal ion in water solution, such as Pb2+ and Cu2+, and the adsorption capacity is 6.18mg/g and4.20mg/g, respectively. The activation energy for adsorbing Pb2+ is about 26.5KJ/mol, and the adsorption frequency factor is 6900S-1. The model parameters solved by non-linear fit is more credible than that by linear fit in simulating the process of Pb2+ adsorption. At the same time, the sludge ramification adsorbent also has good effect on adsorbing sulfur dioxide. On the condition that the percentage of water in adsorbent is about 3 g/lOg (adsorbent), the flux of fume gas about 300L/h, the concentration of sulfur dioxide on the inlet around ISOOppm, and the quantity ofadsorbent 30 g, the adsorption capacity of sulfur dioxide is 60mg/g.