Removal Reaction Research Articles

Enhanced Electrokinetic Remediation of Zinc Contaminated Soil by Changeover of Composite Electrolyte

The combination of electrolytes 0.1 M potassium chloride (KCl) and 0.1 M citric acid (CA) was investigated in a bench scale reactor for removal of zinc (Zn) from soil using electrokinetic remediation (EKR). The study was conducted over a period of 144 hours for different experimental set-ups. When KCl was used as a single electrolyte, 49.38 % removal of zinc was obtained with the changeover of electrolyte at every 24 hours, as compared to 12.5 %, when the reactor was operated as batch reactor without changeover. The use of composite electrolyte in cathode compartment and single electrolyte in anode compartment showed 79.06 % removal, whereas the use of composite electrolyte in both anode and cathode compartment gave 21.74 % removal.

Raw and modified palygorskite in water treatment applications for low-concentration ammonium removal.

Raw palygorskite (Pal) samples went under acid (H-Pal), NaCl (Na-Pal), and CaCl2 treatment (Ca-Pal) in order to be examined as ammonium (NH4 + ) sorbents from aqueous solutions. The samples were characterized by XRD and FT-IR techniques to examine potential structural differences after modifications, and batch kinetic experiment series were applied to determine the optimal conditions for NH4 + removal. According to thermodynamic analysis, the removal reaction for sodium- and calcium-treated samples was endothermic (ΔΗ0 >0, 1.65kJ/mol and 24.66kJ/mol, respectively), in contrast with the exothermic reactions of raw and acidic-treated palygorskite samples (ΔΗ0 <0, -37.18kJ/mol and -27.56kJ/mol respectively). Moreover, each sample presented a different order of sorbed ions preference, whereas the strong affinity for Ca2+ sorption was common in all cases since the NH4 + removal inhibited. Nevertheless, a similar pattern was followed for raw and modified samples at isotherm study, rendering the linear form of Freundlich isotherm to express better the NH4 + sorption on palygorskite sample, indicating that it is a heterogeneous procedure. In all cases, the NH4 + maximum uptake was within 15min using 8g/L of each sorbent, especially for the Na-Pal sample, which could reach almost 100% removal of low concentration NH4 + . PRACTITIONER POINTS: Modified palygorskite samples were tested for NH4 + removal from aqueous solutions. NaCl-treated palygorskite had the higher removal efficiency, which could reach almost 100% removal of low concentration NH4 + . NH4 + maximum uptake was within 15 minutes using 8 g/L of each sorbent. NH4 + adsorption was an endothermic reaction for NaCl- and CaCl2 -treated palygorskite sorbents. NH4 + adsorption was an exothermic reaction for raw and acid-treated palygorskite sorbents.

In-situ pilot-scale passive biochemical reactors for Ni removal from saline mine drainage under subarctic climate conditions

Efficiency of passive bioreactors (PBRs) to treat mine drainage (acid – AMD and neutral – NMD), in northern climates, is evaluated using pilot-scale PBRs installed at the Raglan Mine (Quebec, Canada). Three reactors (PBR-AMD, PBR1-NMD and PBR2-NMD) were filled with reactive mixtures and operated (at hydraulic retention times of 2.5d and 1d, for AMD and NMD) for 48 days, 94 days and 44 days, respectively. The AMD quality was 27.6 mg/L Ni, 23.7 mg/L Fe, 2.4 mg/L Cu, and 3186 mg/L SO42−, at pH 3.6, while the NMD quality was 23.9 mg/L Ni, 0.06 mg/L Fe < 0.003 mg/L Cu, and 587 mg/L SO42−, at pH 7.2. Removal efficiencies of the PBR-AMD reactor were 93–95 % vs 53–56 % Ni (at the beginning and end of the tests, respectively), 96–99 % Fe and 99 % Cu. In the PBR1-NMD reactor, 99 % vs 83 % Ni (in 2017 and 2018, respectively) was removed, while in the PBR2-NMD reactor, 95–99 % vs 61–83 % Ni (at the beginning vs at the end, respectively) was removed. However, all bioreactors failed to meet environmental criteria. None of the bioreactors developed favorable conditions for sulfate reducing bacteria (SRB). Ni retention was likely mainly governed by sorption mechanisms on organic matter or on Fe-oxy-hydroxides. Low temperatures, combined with salinity, may explain the lack of SRB growth in the reactors and the absence of SO42− treatment. The treatment of Cu was not affected by the low temperatures and the primary mechanism of Fe removal in the PBR-AMD reactor was precipitation in the form of oxy-hydroxides.

Preparation and characterization of nano-galvanic bimetallic Fe/Sn nanoparticles deposited on talc and its enhanced performance in Cr(VI) removal

In this study, talc-supported nano-galvanic Sn doped nZVI (Talc-nZVI/Sn) bimetallic particles were successfully synthesized and utilized for Cr(VI) remediation. Talc-nZVI/Sn nanoparticles were characterized by FESEM, EDS, FTIR, XRD, zeta potential, and BET analysis. The findings verified the uniform dispersion of nZVI/Sn spherical nanoparticles on talc surface with a size of 30–200 nm, and highest specific surface area of 146.38 m2/g. The formation of numerous nano-galvanic cells between nZVI core and Sn shell enhanced the potential of bimetallic particles in Cr(VI) mitigation. Moreover, batch experiments were carried out to investigate optimum conditions for Cr(VI) elimination and total Cr(VI) removal was achieved in 20 min using Sn/Fe mass ratio of 6/1, the adsorbent dosage of 2 g/L, initial Cr(VI) concentration of 80 mg/L, at the acidic environment (pH = 5) and temperature of 303 K. Besides, co-existing of metallic cations turned out to facilitate the electron transfer from the nano-galvanic couple of NZVI/Sn, and suggested the revolution of bimetallic particles to trimetallic composites. The aging study of the nanocomposite confirmed its constant high activity during 60 days. The removal reaction was well described by the pseudo-second-order kinetic and the modified Langmuir isotherm models. Overall, due to the synergistic galvanic cell effect of nZVI/Sn nanoparticles and full coverage of active sites by Sn layer, Talc-nZVI/6Sn was utilized as a promising nanocomposite for fast and highly efficient Cr(VI) elimination.

Iron-promoted sulfur sequestration for the substituent-dependent regioselective synthesis of tetrazoles and guanidines

ABSTRACT We have established a facile and versatile synthetic methodology for the construction of tetrazoles and guanidines in the presence of an eco-friendly, inexpensive, easily available iron reagent. Aromatic thioureas with electron-donating substituents produced their respective target products in quantitative yield. In contrast, when electron-withdrawing substituted aromatic thioureas were used, the expected products were obtained in reduced yield. However, the desired products were obtained in good yield at moderate temperature. In addition, mechanistic studies revealed that the synthetic route involved iron-based subsequent reactions of addition and removal of sulfur.

The graceful art, significant function and wide application behavior of ultrasound research and understanding in carbamazepine (CBZ) enhanced removal and degradation by Fe0/PDS/US

Carbamazepine (CBZ) antibiotic organic contamination wastewater poses a huge threat to environmental safety. An advanced oxidation technology (Fe0/PDS/US) of using ultrasound (US) enhanced zero-valent iron/potassium persulfate (Fe0/PDS) can remove CBZ effectively. The optimal reaction conditions were determined by exploring the effect of single-factor experimental conditions such as ultrasonic power, ultrasonic frequency, CBZ concentration, solution pH, PDS dosage, and Fe0 dosage on the removal of CBZ. In addition, we also investigated into the effect of background ions (PO43−, HCO3−, Cl− and HA) on Fe0/PDS/US and analyzed the related results. The mechanism of CBZ removal in Fe0/PDS/US were explored by analyzing CBZ removal efficiency and reaction rates, the ion concentration of S2O82−, SO42−, Fe2+ and Fe3+, pH and the active radicals. The result indicates that US can improve the efficiency of activated PDS and expand the pH range of Fe0/PDS. It has prominent performance in catalytically degrading CBZ when the pH is 10.0. SO4•-, •OH and O2•- all coexist in the Fe0/PDS/US and make contribution to CBZ removal, whereas the SO4•− plays a key role. US can greatly promotes the degradation of target pollutant CBZ by speeding up the dissolution of the outer portion of iron powder, producing sufficient amount of Fe2+ with a continuous and stable way, and better activating S2O82− to generate sufficient SO4•− radicals. The degradation of CBZ may embrace three reaction processes, in which organic intermediate products with low molecular weight and biological toxicity is produced, boosting further mineralization and biodegradation of products. The Fe0/PDS/US is of great potential application value in removal of organic pollution and environmental purification.

Microbial nitrogen removal in synthetic aquaculture wastewater by fixed-bed baffled reactors packed with different biofilm carrier materials

Fixed-bed baffled reactors packed with carbon fiber (CFBR), polyurethane, or non-woven fabrics were developed to support microbial nitrification–denitrification reactions for nitrogen removal from synthetic aquaculture wastewater. The CFBR showed the best performance, with a short hydraulic retention time and low C/N ratio. Microbial communities in the reactor’s biofilms and deposited sludge were analyzed using high-throughput sequencing and quantitative polymerase chain reactions. The biofilms efficiently enriched the nitrifying and denitrifying bacteria in the CFBR. Moreover, bacteria capable of denitrification under aerobic conditions were detected in the aerobic chamber biofilm, showing positive correlations with the main nitrifiers and denitrifiers, which provides potential synergistic interactions for simultaneous nitrification–denitrification in the aerobic chamber. A network analysis revealed that the CFBR had more complex cooperative interactions than others. This study provides insights into the influence of different carrier materials on biofilm formation, proving that the CFBR has potential applications in aquaculture wastewater treatment.

State-of-Art Review of NO Reduction Technologies by CO, CH4 and H2

Removal of nitrogen oxides during coal combustion is a subject of great concerns. The present study reviews the state-of-art catalysts for NO reduction by CO, CH4, and H2. In terms of NO reduction by CO and CH4, it focuses on the preparation methodologies and catalytic properties of noble metal catalysts and non-noble metal catalysts. In the technology of NO removal by H2, the NO removal performance of the noble metal catalyst is mainly discussed from the traditional carrier and the new carrier, such as Al2O3, ZSM-5, OMS-2, MOFs, perovskite oxide, etc. By adopting new preparation methodologies and introducing the secondary metal component, the catalysts supported by a traditional carrier could achieve a much higher activity. New carrier for catalyst design seems a promising aspect for improving the catalyst performance, i.e., catalytic activity and stability, in future. Moreover, mechanisms of catalytic NO reduction by these three agents are discussed in-depth. Through the critical review, it is found that the adsorption of NOx and the decomposition of NO are key steps in NO removal by CO, and the activation of the C-H bond in CH4 and H-H bonds in H2 serves as a rate determining step of the reaction of NO removal by CH4 and H2, respectively.

Modeling and Simulation of Goethite Process for Removal of Iron from Zinc Leaching Solution

A reactor model has been built to simulate the goethite process for iron removal. A three-factor designed set of boundary conditions was applied to determine the effect of stirring speed, gas inlet flow rate, and Fe2+ concentration. The two-phase flow velocity field, gas volume fraction distribution, mass transfer rate, and Fe2+ concentration were obtained as simulation results. The results showed that stirring has a significant effect on the distribution of the fluid field. The reaction rate and mass transfer were greatly influenced by the gas inlet flow rate. Based on the results, the following suggestions can be made for the goethite process for iron removal in this system: the number of stirrers should be increased, and the type and size of stirring paddle should be changed to enhance the fluidity of the solution; the rate of gas inlet flow should be increased to enhance the mass transfer and accelerate the iron removal reaction.

Pre-depositing PAC-birnessite cake layer on gravity driven ceramic membrane (GDCM) reactor for manganese removal: The significance of stable flux and biofilm

Water laden with dissolved manganese ions presents a challenge to water treatment processes and drinking water quality. To address manganese removal, a gravity driven ceramic membrane filtration system was developed; the membrane was pre-modified by depositing freshly formed birnessite type manganese oxide (MnOx) attached on powdered activated carbon (PAC) on the membrane. The result indicated that PAC-MnOx coupled with ceramic membrane rejection enabled the enrichment of manganese oxide bacterial (MnOB) (103 MPN/mL) on the membrane, facilitating biogenetic manganese formation. The dominant MnOB (i.e., Hyphomicrobium) was identified using microbial community analysis. Intermittent dosage of PAC-MnOx at start-up period was likely to generate a cake layer effectively contributing to autocatalytic oxidation; The flux stablised at 41 L/(m2·h) after only 15-d operation, and the permeate of manganese was 0.089 mg/L. After 30-d operation, laser scattering particle analyzer (LASP) revealed that the particles (70.9 μm) within biofilm of gravity driven ceramic membrane (GDCM) grew larger compared with those present initially (48.5 μm) due to the newly formed biogenic MnOx attached to the carrier PAC, indicated by Raman analysis and X-ray Diffraction (XRD) analysis. Mn(III) as the predominant valence in MnOx conferred its outstanding catalytic oxidative capacity, as evidenced by X-ray photoelectron spectroscopy (XPS) analysis. SEM-EDS mapping demonstrated that a uniform flower-like birnessite structure was formed on the PAC surface, facilitating the transformation of MnOx to newly-formed birnessite on the vicinity of GDCM. Taking advantage of PAC and birnessite, the gravity driven filtration system developed in this study is anticipated to be an effective water treatment technique, particularly suitable for small footprint decentralized water supply sanitation.

Arsenic Removal from Highly Contaminated Groundwater by Iron Electrocoagulation—Investigation of Process Parameters and Iron Dosage Calculation

Electrocoagulation (EC) is gaining increased attention for water treatment as it efficiently removes various water contaminants. Therefore, EC was applied to remove arsenic from groundwater of a highly contaminated site in Hamburg, Germany. Groundwater containing 3250 and 14,600 µg/L arsenic, mainly as Arsenite (As(III)), was treated in three different EC batch reactors using a monopolar parallel electrode-configuration. This study focused on iron EC with constant current densities and variable voltage, to investigate the influence of current density, surface to volume ratio, initial arsenic concentration and water volume on the removal of arsenic and the influences on the groundwater composition. Arsenic removal &gt;99.9% was achieved for configurations with high iron dosage after four hours of EC treatment. German drinking water standard for arsenic (&lt;10 µg/L) was obtained after around two hours depending on the applied current densities. Arsenic removal efficiency shows independence from current density, surface to volume ratio, initial concentration and water volume, with respect to the calculated iron dosage. Consequently, the dimensioning and regime of efficient operation of the EC reactor for arsenic removal from groundwater can be calculated solely from the iron dosage determined by the applied current.

Continuous flowing electrocoagulation reactor for efficient removal of azo dyes: Kinetic and isotherm studies of adsorption

Abstract The electrocoagulation process is an effective and economical technology for the treatment of industrial wastewater. So, it is particularly important to develop an efficient electrocoagulation reactor. To this end, a novel electrocoagulation reactor is described to effectively remove azo dyes from aqueous solutions utilizing electrocoagulation, in which the electrode plate is bent. Continuous wastewater flows in the reactor will promote faster and more stable growth of flocs This paper took methyl orange as a study object. It was concluded that methyl orange decolorization rate was 92.35% under the optimal conditions while flat electrode under the same conditions of methyl orange decolorization rate was only 58.9%. The results meant that the second-order kinetic model was most in line with the experimental results, which indicated that the chemisorption mechanism controls the adsorption of methyl orange. Furthermore, the results showed that the Langmuir isotherm model was more in line with the experimental results, and showed that the experiment was single-layer adsorption on the adsorbent surface. Under the optimal conditions of the electrocoagulation process, electrode consumption is 0.2376 g, and the electrical energy consumption is 1.5925 KWh m−3 during a single operation.

Colloidal activated carbon as a highly efficient bifunctional catalyst for phenol degradation

A preparation of colloidal activated carbon (CAC) for phenol remediation from groundwater was introduced. The CAC prepared by a simple pulverization technique was an excellent metal-free catalyst for persulfate (PS) activation due to high contact surface area. The removal efficiency of phenol in the PS/CAC system (~100%) was higher than that in the PS/activated carbon (AC) system (90.1%) and was superior to the conventional PS/Fe2+ system (27.9%) within 30 min. The phenol removal reaction occurred both in bulk solution and at the surface of the CAC, as confirmed by Langmuir–Hinshelwood (L–H) kinetic model fitting, FT−IR, and electron spin resonance (ESR) analyses. The downsizing of particle size from AC to CAC played a critical role in the radical oxidation mechanism by leading to the formation of predominant superoxide radical (O2•–) species in the PS/CAC system. Anions NO3–, SO42−, and Cl– slightly inhibited the phenol removal efficiency, whereas CO32−, HCO3− and PO43− did not. Ferulic acid (C10H10O4) was detected as an organic byproduct of phenol oxidation. The use of CAC as a metal-free bifunctional catalyst has an important implication in the PS activation for phenol degradation in groundwater.

Zinc removal and recovery from industrial wastewater with a microbial fuel cell: Experimental investigation and theoretical prediction

Microbial fuel cells (MFCs) that simultaneously remove organic contaminants and recovering metals provide a potential route for industry to adopt clean technologies. In this work, two goals were set: to study the feasibility of zinc removal from industrial effluents using MFCs and to understand the removal process by using reaction rate models. The removal of Zn2+ in MFC was over 96% for synthetic and industrial samples with initial Zn2+ concentrations less than 2.0 mM after 22 h of operation. However, only 83 and 42% of the zinc recovered from synthetic and industrial samples, respectively, was attached on the cathode surface of the MFCs. The results marked the domination of electroprecipitation rather than the electrodeposition process in the industrial samples. Energy dispersive X-ray (EDX) analysis showed that the recovered compound contained not only Zn but also O, evidence that Zn(OH)2 could be formed. The removal of Zn2+ in the MFC followed a mechanism where oxygen was reduced to hydroxide before reacting with Zn2+. Nernst equations and rate law expressions were derived to understand the mechanism and used to estimate the Zn2+ concentration and removal efficiency. The zero-, first- and second-order rate equations successfully fitted the data, predicted the final Zn2+ removal efficiency, and suggested that possible mechanistic reactions occurred in the electrolysis cell (direct reduction), MFC (O2 reduction), and control (chemisorption) modes. The half-life, t1/2, of the Zn2+ removal reaction using synthetic and industrial samples was estimated to be 7.0 and 2.7 h, respectively. The t1/2 values of the controls (without the power input from the MFC bioanode) were much slower and were recorded as 21.5 and 7.3 h for synthetic and industrial samples, respectively. The study suggests that MFCs can act as a sustainable and environmentally friendly technology for heavy metal removal without electrical energy input or the addition of chemicals.

Performance optimization of a chitosan/anammox reactor in nitrogen removal from synthetic wastewater

Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biological method for nitrogen treatment from aqueous solutions. However, slow growth rate, negative effects of high concentration of nitrite, ammonia and other pollutants (such as metals) on anammox activity are the main drawbacks of using anammox. Thus, in this study, anammox was attached on chitosan to improve anammox performance. Two reactors comprising chitosan and anammox bacteria (first reactor, chitosan/anammox) and solely anammox (second reactor, control) were run for 73 d. The nitrogen loading rate (NLR) varied from 2 to 14 (gN/L/d), while the nitrogen concentration varied from 80 to 700 mg/L. The chitosan/anammox reactor showed a better performance than the sole anammox (control), with respective maximum abatement values of ammonia (NH4+), nitrite (NO2-), and total nitrogen (TN) of 90.8%, 83.5%, and 81.7% on days 20–25 under a NLR of 8–10 kgTN/(m3 d). Response surface methodology (RSM) was employed to optimize the performance of both reactors, and a reasonable R2 value showed that the RSM well optimized the performance of the reactors. After finding the optimum performance conditions for both reactors, Fe and Cu (0.5–7.0 mg/L) were added to the influent to monitor the effects of metals on the performance of both reactors. The performance of both reactors decreased to 0% following the addition of 7.0 (first reactor) and 6.5 (second reactor) mg/L Cu and Fe, respectively. This indicated that chitosan not only enhanced nitrogen removal by anammox but also improved the resistance of anammox to metals.

Recent Advances on Fabrication of Polymeric Composites Based on Multicomponent Reactions for Bioimaging and Environmental Pollutant Removal.

As the core of polymer chemistry, manufacture of functional polymers is one of research hotspots over the past several decades. Various polymers are developed for diverse applications due to their tunable structures and unique properties. However, traditional step-by-step preparation strategies inevitably involve some problems, such as separation, purification, and time-consuming. The multicomponent reactions (MCRs) are emerging as environmentally benign synthetic strategies to construct multifunctional polymers or composites with pendant groups and designed structures because of their features, such as efficient, fast, green, and atom economy. This mini review summarizes the latest advances about fabrication of multifunctional fluorescent polymers or adsorptive polymeric composites through different MCRs, including Kabachnik-Fields reaction, Biginelli reaction, mercaptoacetic acid locking imine reaction, Debus-Radziszewski reaction, and Mannich reaction. The potential applications of these polymeric composites in biomedical and environmental remediation are also highlighted. It is expected that this mini-review will promote the development preparation and applications of functional polymers through MCRs.

Process optimization and adsorption modeling using hierarchical ZIF-8 modified with Lanthanum and Copper for sulfate uptake from aqueous solution: Kinetic, Isotherm and Thermodynamic studies

In the current study, the hieratical zeolitic imidazole framework 8 (H/ZIF-8) and bimetallic H/ZIF-8, H/ZIF-8@La and H/ZIF-8@Cu, were prepared with a simple and green method using water as a solvent. Process parameters (temperature and time of crystallization), as well as compositional parameters (amount of 2-Methylimidazole and 2-(methylamino)ethanol), were studied. H/ZIF-8 samples were characterized with XRD, EDS, FE-SEM, TGA/DTA, FTIR, N2 isotherms, and their performance was evaluated for sulfate uptake from aqueous media. An experimental design was utilized in this study to optimize the independent variables using central composite design (CCD) under the response surface methodology (RSM) method. A significant agreement between the models and experimental data was verified by analysis of variance (ANOVA). The adsorption equilibrium models of Langmuir, Jovanovic, Freundlich, and Temkin isotherms were evaluated and the results described that the Langmuir model was the best with the experimental data. Different kinetic models were estimated and found that pseudo-second-order kinetic data were well-fitted for removal reaction. The determination of different thermodynamic parameters reflected that the sulfate uptake was spontaneous and feasible and that three H/ZIF-8 samples had an endothermic nature. The adsorption on H/ZIF-8 samples was not significantly influenced by the competing anions of nitrate, chloride and fluoride but phosphate displayed slightly greater negative effects. The used H/ZIF-8 samples could be regenerated and reused in eight consecutive cycles with a proper desorption agent. The results of sulfate removal from a real sample revealed that using H/ZIF-8 and two bimetallic H/ZIF-8 samples for sulfate removal from polluted waters is a promising alternative for sulfate recovery.

Porous Organic Polymer Synthesized by Green Diazo-Coupling Reaction for Adsorptive Removal of Methylene Blue.

A porous organic polymer (marked as DT-POP), which contains abundant free phenolic hydroxyl groups, is synthesized by the well-known green azo-coupling reaction in water, characterized, and utilized as an effective adsorbent for the elimination of methylene blue (MB) from water solutions. The presence of permanent mesopores, abundant active functional groups, and π-electron enrichment ascribed to phenyl rings make DT-POP an efficient adsorbent for MB due to strong hydrogen bonding, π–π, and electrostatic interactions with the cationic dye MB. DT-POP with high stability and high adsorption capacity can be reused many times and thus shows high applicability in pollutant disposal.

In-beam γ -ray spectroscopy of Cr62,64

The region of neutron-rich Cr isotopes has garnered much attention in recent years due to a rapid onset of collectivity near neutron number $N=40$. We report here on the first $\ensuremath{\gamma}$-ray spectroscopy beyond the $({4}_{1}^{+})$ state in $^{62,64}\mathrm{Cr}$, using nucleon removal reactions from several projectiles within a rare-isotope beam cocktail. A candidate for the ${6}^{+}$ state in $^{64}\mathrm{Cr}$ is presented as well as one for, possibly, the second excited ${0}^{+}$ state in $^{62}\mathrm{Cr}$. The results are discussed in comparison to the LNPS shell-model predictions that allow for neutron excitations across the $N=40$ harmonic oscillator gap into the ${g}_{9/2}$ and ${d}_{5/2}$ orbitals. The calculated level schemes for $^{62,64}\mathrm{Cr}$ reveal intriguing collective structures. From the predicted neutron particle-hole character of the low-lying states in these Cr isotopes, $^{62}\mathrm{Cr}$ emerges as a transitional system on the path to the center of the $N=40$ island of inversion.

Reaction Kinetics of Ammonium Removal from Cow Urine by Struvite Formation Using a Baffle Column Reactor

Reaction kinetics is the study of reaction rates and reaction mechanisms, which refers to determining the order and reaction rate constants of a given material. This study will examine the kinetics of the reaction of ammonium removal from cow urine by struvite formation. Cow urine contains NH 4 which is high enough so that it can be used as material for the manufacture of struvite. Struvite (MgNH 4 PO 4 .6H 2 O) is a white crystalline material consisting of magnesium, ammonium, and phosphate in equimolar. The experiment was conducted with a temperature setting of 25, 35, 45, and 65 ËšC. The flow rates used were 8.8, 11, 14.67, 22, and 44 mL/min. The process of making struvite was carried out by crystallization at pH 9, molar ratio of 3:1:1, also air rate of 0.4 L/min. The study carried out following the first order with the best conversion was 0.7797 at 8.8 ml/min and 65 ËšC. The activation energy is 3123.82 J/mol and the collision frequency is 0.0379. The equation of reaction rate k = 0.0379 e -375,73/T (K -1 ).