Experimental Study On Adsorption Of Malachite Green And Congo Red By Spent Cottonseed Hull Residue

In this paper we selected two kinds of cheap agricultural by-product of spent cottonseed hull residue of pleurotus ostreatus cultivation(SCHRPO) and spent cottonseed hull residue of flammulina ostreatus cultivation(SCHRFV) as biosorbent, and selected malachite green(MG) and congo red(CR) as adsorbate. A series of batch operation was adopted in experiments.The physical and chemical characteristics of adsorbents were examined by some instruments, such as scanning electronic microscope(SEM), thermogravimetry(TG) and differential scanning calorimetry(DSC), C80trace heat meter, Nicolet Nexus fourier transform infrared spectroscopy(FTIR). According to the static adsorption experiments, the influence of initial pH, time, temperature, adsorbent dose, concentration and salinity to adsorption effect were investigated. In addition, the adsorption thermodynamics and the adsorption kinetics were studied. The main contents and results are following:1. The influence of initial pH, time, temperature, adsorbent dose, concentration and salinity on adsorption was studied in the paper. For the experiments of MG, the removal ration was bigger with the increasing of adsorbent dose. But the removal ration was a little down when the adsorbent dose arrived8g/L in the experiments of adsorbing CR by spent cottonseed hull residue of flammulina ostreatus cultivation. The adsorption quantities and removal ration were increased while the pH rose up4.0when adsorbing MG. But, respectively speaking, the change was not very significant. When the pH changed within the limits of4.0to10.0, the adsorption quantities and removal ration of adsorbing CR by spent cottonseed hull residue of pleurotus ostreatus cultivation were proved a little change in the experiments, and they were the same with adsorbing CR by spent cottonseed hull residue of flammulina ostreatus cultivation. But the adsorption quantities fell observably when the pH was more than10.0. At303K, the maximum adsorption quantities of spent cottonseed hull residue of pleurotus ostreatus cultivation and spent cottonseed hull residue of flammulina ostreatus cultivation binding MG were115.4mg/g and100.8mg/g, respectively. And the maximum adsorption quantities for binding CR were30.9mg/g and40.6mg/g, respectively.2. All the adsorption behavior of the two kinds of edible fungi residue(EFR) adsorbing MG and CR could be approximately described with the Langmuir,emkin and Redlich-Peterson equation. The positive values of△H0suggested the endothermic nature of the adsorption of MG on adsorption. The negative values of△G0at various temperatures indicated the feasibility of the process and spontaneous nature of the adsorption. Also, it was the same result with the adsorption of CR.3. The kinetics of MG and CR adsorption consist of two phases:an initial rapid phase and a slower phase. It was found that the pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior.4. According to the SEM analysis technic, the pictures told that the adsorbents were porous structure with big cells and micro-pores. It was told that exothermic reaction existed in the adsorption process by he results of C80.The direction of the research conforms to the current environmental protection industry policies, which advocate ecological protection and circular economy. The above contents and results will offer a new way to recycling of the mass of edible fungi residue in our country. Furthermore, it provide with a feasible and high-efficiency method to solve the dye wastewater.