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The final concentration shall be the concentration at the end of experiment, for example you're running experiment for 60 min then after 60 min you ll take sample from your solution and filter or centrifuge it, then put it into the cuvette and check the absorbance. And if you want to convert the absorbance into concentration then follow the procedure explained in the video Hope it ll solve the problem

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Thank you very much dear

Thanks for the comment, I used origin for plotting data or graphs

If the concentration levels in the last 30 minutes of your experiment are not showing much decline, and there's no clear slope or trend, you could consider focusing on the time range that best represents the desorption phase (the earlier times where there’s a noticeable slope) for your graph and analysis. If the data before the last 30 minutes provides a clear trend, you might use only that range for your analysis. Mention in your thesis that, due to minimal change observed in the last 30 minutes, this range was excluded.

Thanks for the correction, do the calculations according to your data, regards

Thanks for the informative comment, Yes, optical density (OD) can be expressed as a percentage, often referred to as percent transmittance (%T). The relationship is: %𝑇=10^(−OD)×100 Here, OD is measured logarithmically, so lower OD corresponds to higher transmittance, and vice versa.

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When 𝐶𝑒 =0 (indicating 100% removal efficiency), plotting an isotherm can be challenging since the concentration at equilibrium (Ce) is a key variable. For such cases, you could: Set 𝐶𝑒 to a Very Small Value: Use a near-zero value for 𝐶𝑒 (e.g., 0.001) to approximate the data point. This allows you to plot it on a logarithmic or linear scale without causing issues. Exclude This Point from the Isotherm: Some isotherm models, like the Langmuir or Freundlich, assume non-zero equilibrium concentrations. You can note in your analysis that data points with complete removal (100%) were excluded due to model assumptions. Moreover, if possible, represent the 100% removal point as a boundary or annotate it on your graph to show the extent of removal without needing a specific 𝐶𝑒 value. This approach maintains the integrity of the isotherm while acknowledging the 100% removal scenario.

@@drsaqibscienceacademy Thank you Sir.

If your point of zero charge (pHpzc) is above 7, it means that the surface of your material will be negatively charged at pH values above 7. Since cationic dyes are positively charged, they will be attracted to the negatively charged surface of the material, leading to adsorption of cationic dyes. Conversely, anionic dyes, which are negatively charged, would be repelled by the negatively charged surface and are less likely to adsorb under these conditions.

To calculate the Ct value, take a sample at a specific time point, measure its concentration using an appropriate analytical method (e.g., spectrophotometry), and the measured concentration is your Ct value.

Thank you for your thoughtful questions!. I shall respond point by point. Reaching Equilibrium Practically: In adsorption or chemical reactions, we often take measurements at regular intervals until the concentration stops changing significantly. When consecutive readings are nearly constant, it suggests that equilibrium has been reached. Measuring Concentrations Practically: To measure concentrations before and after equilibrium, samples are taken at specific times, and the concentration is analyzed using techniques like spectrophotometry, titration, or chromatography, depending on the type of substance involved. These measurements help track how the concentration changes over time, showing when equilibrium is achieved. Hope you got my point, if still there is any confusion, you can ask me directly on my WhatsApp given in the videos. regards

@drsaqibscienceacademy Allah bless you,you've covered it all."

@@halaakeelani Thank you very much dear

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Thanks for the correction dear, you are right

Thanks for the correction, yes u r right

Thank you for your question! When the point of zero charge (pzc) of the biosorbent is at pH 6.5, it means the surface is neutral at this pH. At pH values above the pzc (e.g., pH 8), the surface of the biosorbent becomes negatively charged. Since the dye solution is anionic, this negative surface charge at pH 8 would repel anionic dye molecules, potentially impacting dye decolorization efficiency.

Thanks for the question! To measure the concentration of scavengers in your experiment and control for absorption differences, here’s a detailed process you can follow: Prepare the Scavenger Solutions: Start by preparing scavenger solutions at known concentrations. If you’re unsure of the optimal concentration range, try testing several concentrations to observe the scavenger’s effect on the system. Control Absorption Measurement: To establish a baseline, measure the absorbance of the sample without any scavenger present. This control absorbance is crucial to understand the effect of scavengers later on. Use a spectrophotometer or other concentration-measuring device and take measurements at your target wavelength. Sample Absorption with Scavenger: Add the scavenger to the sample and allow it to react for a set period. Measure the absorbance again to see how the scavenger impacts concentration or reaction. Be consistent with timing and conditions between control and sample measurements for accuracy. Calculation of Scavenger Concentration: To determine the concentration, you may use a standard curve or calculate using Beer’s Law (if applicable). Compare the sample and control absorbance values to quantify how much scavenger affects the concentration of the analyte in your system. This method ensures accurate comparisons by factoring in both control and sample conditions, giving a clear understanding of the scavenger’s effect.

Great question dear! In adsorption processes, we often use pseudo-first-order and pseudo-second-order kinetic models instead of simple first-order or second-order rate laws because: Complex Adsorption Mechanisms: The adsorption process typically involves more complex interactions between the adsorbate and the adsorbent surface, which cannot always be fully explained by simple first- or second-order rate equations. These pseudo models are empirical and account for more complex dynamics, such as adsorption site heterogeneity, multi-step processes, or diffusion limitations. Better Fit to Experimental Data: Pseudo-first-order and pseudo-second-order models are often found to better fit experimental data, especially when adsorption involves a combination of surface adsorption and diffusion. These models describe how adsorption rate changes as a function of time, taking into account the potential for adsorption to become slower as sites are occupied. Saturation Effect: In pseudo-second-order models, the rate of adsorption slows down as the available adsorption sites become occupied. This is more realistic because as more molecules are adsorbed, the remaining sites for adsorption become fewer, causing a decrease in the rate. The pseudo-first-order model, on the other hand, accounts for the situation when the adsorption rate is proportional to the difference between the surface concentration and the equilibrium concentration.

@@drsaqibscienceacademy oh thank you for your explanation, sir. I wish you all the best ❤

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you can email me dr abu hassaan at gmail or s a q i 7 8 at g m a i l all this is without spaces

In the experiment, qe refers to the equilibrium adsorption capacity, which corresponds to the value of the adsorbate concentration at equilibrium, typically represented by 𝐶𝑒. So, 𝑞𝑒 corresponds to the value at equilibrium (i.e., 𝐶𝑒 ), not specifically at 3 hours unless the system reaches equilibrium at that time. If equilibrium is reached before 3 hours, 𝑞𝑒 would be measured at that equilibrium concentration, not necessarily at the 3-hour mark.

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The use of logarithmic (log) and natural logarithmic (ln) transformations in adsorption studies helps for the following reasons: Linearization of Data: Adsorption isotherms (like Freundlich or Langmuir) often do not follow a linear relationship between 𝐶𝑒 (equilibrium concentration) and 𝑞𝑒 (adsorption capacity). By applying log or ln transformations, you can linearize these data points, making it easier to apply mathematical models and determine adsorption parameters. Simplification of Complex Relationships: Adsorption processes often involve non-linear kinetics, and logarithmic transformations simplify these relationships, making it easier to identify trends and predict adsorption behavior. Wide Range of Values: Concentrations and adsorbed quantities can vary over a wide range. Using log or ln scales compresses large values, allowing for a more manageable representation and comparison of data. Better Fit to Models: Many adsorption models are based on equations that are logarithmic in nature, and applying log or ln allows the data to match these models more closely, improving the accuracy of fitting and analysis.

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I usually use Origin, but sometimes I also use MS Excel.

"Thank you for your comment, Torphy Hill! I'm glad you found the video interesting. If you have any questions or need further clarification, feel free to ask!"

Thank you for your comment, Yes, the graph of the Freundlich adsorption model can show a decreasing slope, depending on the nature of the adsorption process. Moreover, the slope can decrease depending on the value of 1/n, which reflects the degree of heterogeneity in the adsorption sites.

If you're incorporating the Van't Hoff equation or other thermodynamic parameters (like Δ𝐺, ΔH, or ΔS) in your analysis, the graph might show a change in slope depending on the heat of adsorption and whether the process is endothermic or exothermic. So, yes, depending on how temperature and thermodynamic parameters are accounted, the graph could exhibit an increasing slope under certain conditions.

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Thank you for the comment and a wonderful question, thickness (cm) and wavelength (nm) are used in absorption and spectroscopic measurements for the following reasons: Thickness (cm): The path length of the sample affects how much light is absorbed. The thicker the sample, the more light interacts with it, which increases the absorbance. Wavelength (nm): Different substances absorb light at specific wavelengths. The wavelength (in nanometers) is crucial because it determines the energy of the light and the specific absorption characteristics of the substance being measured. Both factors are needed for accurate analysis of light absorption and to apply laws like Beer-Lambert for concentration determination.

@@drsaqibscienceacademy thank you so much for your collaboration professor

To calculate the Ct value, take a sample at a specific time point, measure its concentration using an appropriate analytical method (e.g., spectrophotometry), and the measured concentration is your Ct value.

Thank you so much! It depends on the type of equation you're using. In the linear form, there are two variations: one uses the intercept, while the other uses the slope. So, determine whether to use the intercept or slope based on your specific equation to find qmax.

Thank you so much for an informative comment, I shall try to use the cluster method as well. You are wonderful Dr. Wazir! Wonderful people leave wonderful comments-I'm truly grateful to have viewers like you.

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Thank you so much for a wonderful comment, and apologies for late response. Yes, it is generally acceptable to use the Ce value (equilibrium concentration) measured at 24 hours, as long as the system has reached equilibrium by that time. Many adsorption experiments use a 24-hour time frame to ensure equilibrium is achieved, especially for slower adsorption processes. However, there are a few things to consider: Confirm Equilibrium: Make sure that the adsorption process has truly stabilized by 24 hours. If the removal percentage has plateaued and there’s no significant change in the concentration after 24 hours, it’s reasonable to assume equilibrium is reached. Consistency with Literature: If the majority of similar studies or models in the literature determine Ce at 24 hours, then it is fine to use this value in your isotherm and kinetic plots, as it aligns with standard practice in the field. Time-Dependent Kinetics: If you’re also plotting kinetic data, be mindful that using data points beyond the equilibrium phase (after 24 hours) may not accurately reflect the kinetic model's behavior, as the process will be slower and closer to equilibrium. So, if the adsorption process has stabilized by 24 hours, your approach is valid, but make sure to clearly mention that Ce was measured at 24 hours in your analysis.

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Thanks for the comment, I have detailed video on this, please visit my channel and watch it out, dont forget to thumbs up dear

Good day! I'm glad to hear that the videos have been helpful to you. In the Elovich model, the data point at 0 minutes is often excluded because this model focuses on the later stages of adsorption, where the rate slows down, and the initial data might skew the analysis. However, in Pseudo First Order (PFO) and Pseudo Second Order (PSO) models, the 0-minute data is included to establish the initial condition of the system, which is crucial for accurately calculating the adsorption rate over time.

In Sha Allah, I shall upload in near future, take care

Thanks for the comment, a positive value in intraparticle diffusion suggests the presence of other factors (like boundary layer resistance) affecting the adsorption process, not just the diffusion of adsorbate within the pores of the adsorbent.

I'm really glad my video was helpful to you! If you have any more questions or need further clarification, feel free to ask. Thank you for the kind words! ❤

@@drsaqibscienceacademy thnks 4 this honour sir ❤️

I'm really glad my video was helpful to you! If you have any more questions or need further clarification, feel free to ask. Thank you for the kind words! ❤

I'm really glad my video was helpful to you! If you have any more questions or need further clarification, feel free to ask. Thank you for the kind words! ❤