A Experimental Research Of Treating Coking Wastewater By A Novel Nano-Xonotlite Material

As the State Environmental Protection Agency's new requirement of environmental protection and targets of energy saving and pollution reducing,the quality of the effluent water from all the sewage treatment system of phenol-cyanogen wastewater must meet the first grade of the national discharge standards till 2009,it was completely accorded with the principle to develop circular economy through minimisation,reuse,resource which were proposed in the 11th Five-Year-Plan to carry on experimental research on the treatment of coking wastewater by the novel nano-xonotlite material and to launch the adsorbent product as well as to unify this product with other processing crafts.The experimental research were mainly conducted of the static and dynamic's kinetics and the influence factors in this article through carrying on the experiment of adsorbing the coking wastewater's ammonia nitrogen and COD by the novel nano-xonotlite material.On this basis,the experiment of the material's adsorption kinetics performance and the continuous running control experiment in view of the coking wastewater and the type of wastewater containing ammonia nitrogen were also carried on in order to study on the feasibility and the adsorption effect of the nano-xonotlite material which serves as the novel water treatment adsorbent,and then optimize the technological parameter and the operating condition.The static adsorption experimental research was carried out to investigate the effect of treating coking wastewater's ammonia nitrogen by analysing the factors such as the wastewater's pH,the grain size of xonotlite,xonotlite's quantity,the initial water quality and the stiring time.The best static experimental condition was that:under the room temperature,the stiring freguency is 200r/min,the pH value is 8,xonotlite's granularity is 0.022mm⁰.2mm,the quantity is 3.0g/100ml,the wastewater's initial ammonia nitrogen concentration is 89.97mg/L, the stiring time is 180min.With these conditions,the material's adsorptive experiment has been carried on.The adsorption mechanism was discussed based on Langmuir isotherm and Freundlich isotherm in order to seek the suitable adsorption theory pattern and reveal the xonotlite's adsorption characteristic and mechanism.The adsorptive experiment of the xonotlite and the activated carbon were compared,and the results indicated that:the effect was optimal when dosing quantity was 2.5g/100ml,the NH₃-N adsorptive capacity between xonotlite and activated carbon were 1.35mg/g and 1.60mg/g,the NH3- N removal rate were 45.55% and 47.25%,respectively.The dynamic experiment can inspect the adsorption performance and the influenc factors under the closer and actual condition of water treatment.The bench-scale dynamic adsorption test was carried out to investigate the effect of treating coking wastewater's ammonia nitrogen and COD by analysing the factors such as xonotlite's pillar altitude,the grain size of xonotlite and the water's initial quality,and the experimental verifying was also carried out.Taking the ammonia nitrogen removal rate as the target,the best dynamic adsorption experimental condition was:under the room temperature,the pH value is 8,the wastewater's initial NH3-N concentration is 21.33mg/L,xonotlite's granularity is 40-80 mesh,xonotlite's pillar altitude is 300mm,the velocity of effluent is 0.6ml/min,when the accumulation nominal flow reached to 75ml,the ammonia nitrogen removal rate is 80.22 %,the COD removal rate is under 10%.Taking the COD removal rate as the target,the best dynamic adsorption experimental condition was that:under the room temperature,the pH value is 8,xonotlite's granularity is 20-40 mesh,xonotlite's pillar altitude is 400mm,the wastewater's initial COD concentration is 321.1mg/L,the velocity of effluent is 1.2ml/min,when the accumulation nominal flow is reached to 75ml,the ammonia nitrogen removal rate is 58.28%,the COD removal rate is under 10%.The processing effect of the dynamic adsorption experiment was obviously better than that of the static adsorption experiment,and the ammonia nitrogen removal effect was obviously better than the COD removal effect.On this basis,the continuous running experiment was also carried on in view of the coking wastewater and the type of wastewater containing ammonia nitrogen with xonotlite's filter column.Contrast analyze has been done of the removal effect of the turbidity (NTU) and the ammonia nitrogen (NH₃-N),purpose to study on the the practical application value of the nano-xonotlite material which serves as the novel water treatment adsorbent treating the coking wastewater.