Water pollution caused by ammonia nitrogen is of major concern in many parts of the world due to the danger it poses to the environment and human health.This study focuses on the development of an inexpensive and envi...Water pollution caused by ammonia nitrogen is of major concern in many parts of the world due to the danger it poses to the environment and human health.This study focuses on the development of an inexpensive and environmental adsorbent by means of modified corncob.The objective of this paper was to investigate the adsorption behavior of NH^+_4-N from wastewater by modified corncob.Corncob was modified with KMn O_4.The physico-chemical properties of modified corncob were characterized by fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).It was found that the adsorption capacity of corncob was improved significantly after modification with KMn O_4.The p H significantly affected the adsorption efficiency of modified corncob to NH^+_4-N.The best p H value of corncob adsorbing NH^+_4-N was 7.The coexistence of Na^+had a significant effect on the adsorption of NH^+_4-N.The adsorption process of modified corncob to NH^+_4-N followed the pseudo-first order kinetic model.Langmuir model could well simulate the adsorption behavior of NH^+_4-N on modified corncob.The maximum adsorption capacity of NH^+_4-N on modified corncob can reach 4.85 mg/g.The adsorption process of NH^+_4-N was monolayer adsorption.Moreover,modified corncob adsorbed NH^+_4-N was fertilizer conservation especially for nitrogen.The utilization of modified corncob with NH^+_4-N adsorption in the farmland could promote the gradual release of nutrients,thus providing nutrients for plant growth.It was proposed that if combined with biological method,the amount of removed NH^+_4-N from wastewater could be increased significantly.展开更多
With the application of chromium increasing, wastewater shows an increase of chromium pollution. In particular, Cr(Ⅵ) has become a major concern because of its high toxicity. Cr(Ⅵ) is recognized to be much more toxi...With the application of chromium increasing, wastewater shows an increase of chromium pollution. In particular, Cr(Ⅵ) has become a major concern because of its high toxicity. Cr(Ⅵ) is recognized to be much more toxic than Cr(Ⅲ). Sugarcane residue is a byproduct of the sugar industry, and it is an important renewable biomass resource. In this paper, sugarcane residues were used to remove chromium ions from wastewater in order to develop cheap and efficient heavy metal adsorption materials. The effects of pH, sugarcane residue dosage, sugarcane residue particle size and chromium ion initial concentration on chromium ion removal and the kinetics of chromium ion removal at normal temperature were investigated. The results showed that the removal rate of Cr(Ⅵ) and Cr(Ⅲ) increased with an increase of sugarcane residue concentration, and decreased with an increase of particle size and the initial concentration of chromium. The removal effect of Cr(Ⅲ) increased with increasing pH, and the removal effect of Cr(Ⅵ) decreased with increasing pH. The removal kinetics of chromium fitted well with a pseudo-second-order-model. Sugarcane residues had a higher adsorption capacity for Cr(Ⅲ) than for Cr(Ⅵ). This paper provides a basis for the treatment of chromium containing wastewater or other heavy metal wastewater in the future.展开更多
文摘Water pollution caused by ammonia nitrogen is of major concern in many parts of the world due to the danger it poses to the environment and human health.This study focuses on the development of an inexpensive and environmental adsorbent by means of modified corncob.The objective of this paper was to investigate the adsorption behavior of NH^+_4-N from wastewater by modified corncob.Corncob was modified with KMn O_4.The physico-chemical properties of modified corncob were characterized by fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).It was found that the adsorption capacity of corncob was improved significantly after modification with KMn O_4.The p H significantly affected the adsorption efficiency of modified corncob to NH^+_4-N.The best p H value of corncob adsorbing NH^+_4-N was 7.The coexistence of Na^+had a significant effect on the adsorption of NH^+_4-N.The adsorption process of modified corncob to NH^+_4-N followed the pseudo-first order kinetic model.Langmuir model could well simulate the adsorption behavior of NH^+_4-N on modified corncob.The maximum adsorption capacity of NH^+_4-N on modified corncob can reach 4.85 mg/g.The adsorption process of NH^+_4-N was monolayer adsorption.Moreover,modified corncob adsorbed NH^+_4-N was fertilizer conservation especially for nitrogen.The utilization of modified corncob with NH^+_4-N adsorption in the farmland could promote the gradual release of nutrients,thus providing nutrients for plant growth.It was proposed that if combined with biological method,the amount of removed NH^+_4-N from wastewater could be increased significantly.
文摘With the application of chromium increasing, wastewater shows an increase of chromium pollution. In particular, Cr(Ⅵ) has become a major concern because of its high toxicity. Cr(Ⅵ) is recognized to be much more toxic than Cr(Ⅲ). Sugarcane residue is a byproduct of the sugar industry, and it is an important renewable biomass resource. In this paper, sugarcane residues were used to remove chromium ions from wastewater in order to develop cheap and efficient heavy metal adsorption materials. The effects of pH, sugarcane residue dosage, sugarcane residue particle size and chromium ion initial concentration on chromium ion removal and the kinetics of chromium ion removal at normal temperature were investigated. The results showed that the removal rate of Cr(Ⅵ) and Cr(Ⅲ) increased with an increase of sugarcane residue concentration, and decreased with an increase of particle size and the initial concentration of chromium. The removal effect of Cr(Ⅲ) increased with increasing pH, and the removal effect of Cr(Ⅵ) decreased with increasing pH. The removal kinetics of chromium fitted well with a pseudo-second-order-model. Sugarcane residues had a higher adsorption capacity for Cr(Ⅲ) than for Cr(Ⅵ). This paper provides a basis for the treatment of chromium containing wastewater or other heavy metal wastewater in the future.
