This paper presents the kinetic and functional parametric behavior of cocoyam coagulant (CYC) in respect of pH and time variation in brewery effluent at room temperature. The study employed standard nephelometric jar ...This paper presents the kinetic and functional parametric behavior of cocoyam coagulant (CYC) in respect of pH and time variation in brewery effluent at room temperature. The study employed standard nephelometric jar test while CYC production was based on method reported by Ndabigengesere. Coag-flocculation parameter such as order of reaction α, rate constant K, coagulation period, τ1/2 etc. were determined. Maximum parameter values are recorded at K of 6 × 10-1 L/mg·min;dosage of 200 mg/L, pH 8 and τ1/2 of 0.00146 min while the minimum values are recorded at 3 × 10-7 L/mg, dosage of 100 mg/L, pH 10 and τ1/2 of 20.4 min. The maximum coag-flocculation efficiency E (%) obtained was 92.28, thus establishing CYC as a potential effective coag-flocculaant.展开更多
Simultaneous orthokinetic and perikinetic coagulations（SOPCs） are studied for small and large Peclet numbers（P e） using Brownian dynamics simulation.The results demonstrate that the contributions of the Brownian m...Simultaneous orthokinetic and perikinetic coagulations（SOPCs） are studied for small and large Peclet numbers（P e） using Brownian dynamics simulation.The results demonstrate that the contributions of the Brownian motion and the shear flow to the overall coagulation rate are basically not additive.At the early stages of coagulation with small Peclet numbers,the ratio of overall coagulation rate to the rate of pure perikinetic coagulation is proportional to P 1/2 e,while with high Peclet numbers,the ratio of overall coagulation rate to the rate of pure orthokinetic coagulation is proportional to P 1/2 e.Moreover,our results show that the aggregation rate generally changes with time for the SOPC,which is different from that for pure perikinetic and pure orthokinetic coagulations.By comparing the SOPC with pure perikinetic and pure orthokinetic coagulations,we show that the redistribution of particles due to Brownian motion can play a very important role in the SOPC.In addition,the effects of redistribution in the directions perpendicular and parallel to the shear flow direction are different.This perspective explains the behavior of coagulation due to the joint effects of the Brownian motion（perikinetic） and the fluid motion（orthokinetic）.展开更多
The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions in studies on dynamic behaviour of a colloidal system. However, t...The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions in studies on dynamic behaviour of a colloidal system. However, the associated changes in the solvent composition may bring side effects to the properties investigated and therefore might lead to a faulty conclusion if the relevant correction is not made. To illustrate the importance of this side effect, we present an example of the sedimentation influence on the coagulation rate of suspensions of 2μm （diameter） polystyrene. The liquid mixtures, in the proper proportions of water （H2O）, deuterium oxide （D2O） and methanol （MeOH） as the liquid phase, density-matched and unmatched experiments are performed. Besides the influence of viscosity, the presence of methanol in solvent media, used to enhance the sedimentation effect, causes significant changes （reduction） in rapid coagulation rates compared to that in pure water. Without the relevant corrections for those non-gravitational factors it seems that gravitational sedimentation would retard the coagulation. The magnitude of the contribution from the non-gravitational factor is quantitatively determined, making the relevant correction possible. After necessary the influence of the sedimentation on coagulation rates at corrections for all factors, our experiments show that the initial stage of the coagulation is not observable.展开更多
An experimental set up was designed to separately test how sedimentation and convection driven flows affect the perikinetic coagulation process in a ground based experiment.The experiment showed that the sedimentation...An experimental set up was designed to separately test how sedimentation and convection driven flows affect the perikinetic coagulation process in a ground based experiment.The experiment showed that the sedimentation slightly accelerates the coagulation process and weak free convection driven flows do not noticeably contribute to coagulation for 2 μm particles’ dispersion.展开更多
In this study, Mucuna flagellipes seed extract was applied in the coagulation-flocculation of produced water （PW）. Process parameters such as pH, dosage, and settling time were investigated. Process kinetics was als...In this study, Mucuna flagellipes seed extract was applied in the coagulation-flocculation of produced water （PW）. Process parameters such as pH, dosage, and settling time were investigated. Process kinetics was also studied. Instrumental characterization of mucuna seed （MS）, mucuna seed coagulant （MSC）, and post effluent treatment settled sludge （PTSS） were carried out. The optimum decontamination efficiency of 95 % was obtained at 1 g/L MSC dosage, PW pH of 2, and rate constant of 0.0001 （L/g/s）. Characterization results indicated that MS, MSC, and PTSS were of network structure, primitive lat- tice, and thermally stable. It could be concluded that MSC would be potential biomass for the treatment of produced water under the experimental conditions.展开更多
The effectiveness of locally available okra pod powder as natural coagulant under varying pH, dosage and settling time in the removal of turbidity from paint waste water at room temperature has been evaluated. The app...The effectiveness of locally available okra pod powder as natural coagulant under varying pH, dosage and settling time in the removal of turbidity from paint waste water at room temperature has been evaluated. The application of single angle Turbidimeter measurement was employed for the experiment. Such kinetic and functional parameter as coagulation rate constant (K), and coagulation period (τ1/2) , were determined. Statistical parameters such as coefficient of determination (R2), sum of squares due to error (SSE), and the root mean square error (RMSE), were used to evaluate the adequacy of the process. The highest value of 1.7×10﹣4L/mg.min for K is recorded at pH 4 and 100 mg/L dosage with?τ1/2 of 14.91 min and the least value of K, 3.6×10﹣5L/mg.min is recorded at pH 8 and 300 mg/L doses with τ1/2 of 70.43 min respectively. The efficiency of turbidity removal of more than 80% and 95% was achieved at the end of 3 mins and 30 mins settling time respectively, indicating a system controlled by perikinetic method of coag-flocculation. The results exhibited the potential of pulverized okra pod for removal of suspended particle from paint wastewater.展开更多
文摘This paper presents the kinetic and functional parametric behavior of cocoyam coagulant (CYC) in respect of pH and time variation in brewery effluent at room temperature. The study employed standard nephelometric jar test while CYC production was based on method reported by Ndabigengesere. Coag-flocculation parameter such as order of reaction α, rate constant K, coagulation period, τ1/2 etc. were determined. Maximum parameter values are recorded at K of 6 × 10-1 L/mg·min;dosage of 200 mg/L, pH 8 and τ1/2 of 0.00146 min while the minimum values are recorded at 3 × 10-7 L/mg, dosage of 100 mg/L, pH 10 and τ1/2 of 20.4 min. The maximum coag-flocculation efficiency E (%) obtained was 92.28, thus establishing CYC as a potential effective coag-flocculaant.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10972217,10932012 and 11032011)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KJCX2-YW-L08)
文摘Simultaneous orthokinetic and perikinetic coagulations（SOPCs） are studied for small and large Peclet numbers（P e） using Brownian dynamics simulation.The results demonstrate that the contributions of the Brownian motion and the shear flow to the overall coagulation rate are basically not additive.At the early stages of coagulation with small Peclet numbers,the ratio of overall coagulation rate to the rate of pure perikinetic coagulation is proportional to P 1/2 e,while with high Peclet numbers,the ratio of overall coagulation rate to the rate of pure orthokinetic coagulation is proportional to P 1/2 e.Moreover,our results show that the aggregation rate generally changes with time for the SOPC,which is different from that for pure perikinetic and pure orthokinetic coagulations.By comparing the SOPC with pure perikinetic and pure orthokinetic coagulations,we show that the redistribution of particles due to Brownian motion can play a very important role in the SOPC.In addition,the effects of redistribution in the directions perpendicular and parallel to the shear flow direction are different.This perspective explains the behavior of coagulation due to the joint effects of the Brownian motion（perikinetic） and the fluid motion（orthokinetic）.
基金Supported by the National Natural Science Foundation of China under Grant Nos 20473108 and 10332050, and the Knowledge Innovation Program of Chinese Academy of Sciences.
文摘The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions in studies on dynamic behaviour of a colloidal system. However, the associated changes in the solvent composition may bring side effects to the properties investigated and therefore might lead to a faulty conclusion if the relevant correction is not made. To illustrate the importance of this side effect, we present an example of the sedimentation influence on the coagulation rate of suspensions of 2μm （diameter） polystyrene. The liquid mixtures, in the proper proportions of water （H2O）, deuterium oxide （D2O） and methanol （MeOH） as the liquid phase, density-matched and unmatched experiments are performed. Besides the influence of viscosity, the presence of methanol in solvent media, used to enhance the sedimentation effect, causes significant changes （reduction） in rapid coagulation rates compared to that in pure water. Without the relevant corrections for those non-gravitational factors it seems that gravitational sedimentation would retard the coagulation. The magnitude of the contribution from the non-gravitational factor is quantitatively determined, making the relevant correction possible. After necessary the influence of the sedimentation on coagulation rates at corrections for all factors, our experiments show that the initial stage of the coagulation is not observable.
文摘An experimental set up was designed to separately test how sedimentation and convection driven flows affect the perikinetic coagulation process in a ground based experiment.The experiment showed that the sedimentation slightly accelerates the coagulation process and weak free convection driven flows do not noticeably contribute to coagulation for 2 μm particles’ dispersion.
文摘In this study, Mucuna flagellipes seed extract was applied in the coagulation-flocculation of produced water （PW）. Process parameters such as pH, dosage, and settling time were investigated. Process kinetics was also studied. Instrumental characterization of mucuna seed （MS）, mucuna seed coagulant （MSC）, and post effluent treatment settled sludge （PTSS） were carried out. The optimum decontamination efficiency of 95 % was obtained at 1 g/L MSC dosage, PW pH of 2, and rate constant of 0.0001 （L/g/s）. Characterization results indicated that MS, MSC, and PTSS were of network structure, primitive lat- tice, and thermally stable. It could be concluded that MSC would be potential biomass for the treatment of produced water under the experimental conditions.
文摘The effectiveness of locally available okra pod powder as natural coagulant under varying pH, dosage and settling time in the removal of turbidity from paint waste water at room temperature has been evaluated. The application of single angle Turbidimeter measurement was employed for the experiment. Such kinetic and functional parameter as coagulation rate constant (K), and coagulation period (τ1/2) , were determined. Statistical parameters such as coefficient of determination (R2), sum of squares due to error (SSE), and the root mean square error (RMSE), were used to evaluate the adequacy of the process. The highest value of 1.7×10﹣4L/mg.min for K is recorded at pH 4 and 100 mg/L dosage with?τ1/2 of 14.91 min and the least value of K, 3.6×10﹣5L/mg.min is recorded at pH 8 and 300 mg/L doses with τ1/2 of 70.43 min respectively. The efficiency of turbidity removal of more than 80% and 95% was achieved at the end of 3 mins and 30 mins settling time respectively, indicating a system controlled by perikinetic method of coag-flocculation. The results exhibited the potential of pulverized okra pod for removal of suspended particle from paint wastewater.
