Biosorption characteristics of unicellular green alga Chlorella sorokiniana immobilized in loofa sponge for removal of Cr(Ⅲ)

Loofa sponge （LS） immobilized biomass of Chlorella sorokiniana （LSIBCS）, isolated from industrial wastewater, was investigated as a new biosorbent for the removal of Cr（Ⅲ） from aqueous solution. A comparison of the biosorption of Cr（Ⅲ） by LSIBCS and free biomass of C. sorokiniana （FBCS） from 10-300 mg Cr（Ⅲ）/L aqueous solutions showed an increase in uptake of 17.79% when the microalgal biomass was immobilized onto loofa sponge. Maximum biosorption capacity for LSIBCS and FBCS was found to be 69.26 and 58.80 mg Cr（Ⅲ）/g biosorbent, respectively, whereas the amount of Cr（Ⅲ） ions adsorbed onto naked LS was 4.97 mg/g. The kinetics of Cr（Ⅲ） biosorption was extremely rapid and equilibrium was established in about 15 and 20 min by LSIBCS and FBCS, respectively. The biosorption equilibrium was well defined by Langmuir adsorption isotherm model. The biosorption kinetics followed the pseudo-second order kinetic model. The biosorption was found to be pH dependent and the maximum sorption occurred at the solution pH 4.0. Desorption studies showed that 98% of the adsorbed Cr（Ⅲ） could be desorbed with 0.1 mol/L HNO3, while other desorbing agents were less effective in the order： EDTA 〉 H2SO4 〉 CH3COOH 〉 HCl. The regenerated LSIBCS retained 92.68% of the initial Cr（Ⅲ） binding capacity up to five cycles of reuse in continuous flow-fixed bed columns. The study revealed that LSIBCS could be used as an effective biosorbent for the removal of Cr（Ⅲ） from wastewater.

Pigment Adsorption Optimization in Various Low Cost Adsorbents

The applications of adsorption are very important.The following is a list of some of the most common:using the adsorption effect we can achieve a high vacuum in cases of low temperature at which the adsorption of gases from solids is intense.Regarding,the gap we can achieve is in the range of 10-7 mmHg.Another very important application of adsorption is the separation of a mixture of gases from a certain adsorbent,which has a separate adsorption capacity for each gas.In this way it is possible to separate the noble gases,as well as gasoline and hexanes from oil.The experimental diagrams confirm the validity of the Freundlich equation for dilute solutions with low concentrations.At the same time,from the aggregate diagrams of the dilute solutions,listed above,we observe:for graph 1 concerning the adsorbent materials we used we observe that the capacity KF has a higher value for the ground cork while the lower one for olive ash.Also,for graph 2 regarding the adsorbent materials we used we observe the n of the isothermal Freundlich has a maximum for olive ash while a minimum has for two materials lentil straw and ground cork.

Effect of Thermal Regeneration on the Breakthrough Performance of Ceramsite Saturated with Methylene Blue

The regeneration of a spent packing is crucial with respect to the development of circular economy and abstemious society.Thus,the effects of regeneration temperature,resistant time,heating rate,and regeneration cycle on the breakthrough performance of methylene blue(MB)dye⁃exhausted ceramsite in a two⁃stage fixed⁃bed column were studied in this work.Results illustrate that the ceramsite exhibited excellent potential regeneration properties under the following optimal regeneration conditions:treatment temperature was 600°C,resistant time was 15 min,heating rate was 20℃/min,regeneration cycle was over 9 cycles,and the breakthrough time,saturation time,regeneration efficiency(RE),and regeneration loss rate(RLR)were 540 min,1020 min,64.61%,and 17.73%,respectively.The RE declined by 35.14%in over 1 cycle,while the RLR increased by 3.15 times in over 9 cycles.Besides,Thomas model was suitable to describe the two⁃stage fixed⁃bed column adsorption and thermal regeneration process with R2=0.978.In conclusion,a thorough understanding of the regeneration behavior of the two⁃stage fixed⁃bed column packed with ceramsite provides reference to obtain an effective and feasible regeneration approach,and it is beneficial for further application in water treatment.