Struvite Research Articles

Imparting a better corrosion resistance and bioactivity for magnesium through the formation of zinc - zinc oxide - zinc phosphate (hopeite) - magnesium ammonium phosphate (struvite) composite coatings

The present study aims to develop zinc-zinc oxide-zinc phosphate (hopeite)-magnesium ammonium phosphate (struvite) composite coatings to reduce the rate of degradation and to impart a better bioactivity for Mg. Galvanic deposition was employed to form Zn-ZnO coating on Mg, which was subsequently converted to hopeite and struvite by chemical conversion method using diammonium hydrogen phosphate. The structural and morphological characteristics, nature of functional groups, degradation behaviour in Hanks’ balanced salt solution (HBSS) and bioactivity in simulated body fluid (SBF) were evaluated. The findings of the study revealed that Zn-ZnO-hopeite-struvite composite coating has considerably reduced the rate of degradation of Mg in HBSS and promoted the bioactivity of Mg in SBF. The rate of degradation of Mg is decreased from 1.27 ± 0.11 mm/y to 0.13 ± 0.04 mm/y, amounting to ⁓90 % reduction in the corrosion rate. The morphological features reveal that the extent of corrosion attack on Zn-ZnO-hopeite-struvite composite coated Mg is very much limited when compared to that of the uncoated one. The surface of Zn-ZnO-hopeite-struvite composite coated Mg shows many thin needle-like crystals as well as globular-like particles after immersion in SBF when compared to that of uncoated and Zn-ZnO coated Mg. The uniform and compact coating with good adherence, improved corrosion resistance and better bioactivity suggest that Zn-ZnO-hopeite-struvite composite coating is a promising surface modification approach towards the development of Mg-based degradable implants.

Corrosion Resistance of Magnesium Ammonium Phosphate Cement-Based Coatings Modified by Calcium Sulfoaluminate Cement on Carbon Steel in a Saline Medium

Corrosion Resistance of Magnesium Ammonium Phosphate Cement-Based Coatings Modified by Calcium Sulfoaluminate Cement on Carbon Steel in a Saline Medium

COMPLEX TITANIUM-CONTAINING REAGENTS IN WASTEWATER TREATMENT PROCESSES OF THE FISHING INDUSTRY

The issues of removing nutrients from wastewater from various industries have recently received more and more attention. Traditional coagulants based on aluminum and iron salts can effectively remove phosphate ions from water, but these reagents are not effective against ammonium ions. As part of the work done, the possibility of using complex titanium-containing coagulants in the processes of dephosphatization of wastewater from the fish processing industry was considered. It has been proven that the use of magnesium titanium reagents makes it possible to carry out the coprecipitation of ammonium and phosphate ions in the form of the complex compound of magnesium ammonium phosphate (struvite) with high efficiency. To implement the purification process, a 10–20% stoichiometric excess of magnesium compounds from the calculated value is required, while the efficiency of precipitation of ammonium compounds exceeds 50%, and phosphate anion 95%. The optimal pH range for the process of coprecipitation of ammonium and phosphate ions in the form of a complex compound is 10.0 – 10.5. The results of studies conducted on real water from a fish processing plant demonstrated the increased efficiency of complex titanium-containing reagents compared to traditional coagulants based on aluminum, iron and magnesium salts. The possibility of using magnesium-containing waste from the production of refractory materials has been established both as a precursor for the production of complex coagulants and as an individual reagent. It has been proven that the use of complex titanium-containing reagents makes it possible to significantly intensify the processes of sedimentation (15%) and filtration (20%) of coagulation sludge. The use of complex reagents will significantly increase the level of environmental safety of production and reduce the anthropogenic load on the hydrosphere. For citation: Kuzin E.N. Complex titanium-containing reagents in wastewater treatment processes of the fishing industry. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 127-135. DOI: 10.6060/ivkkt.20246707.6997.

An Overview on Kidney Stone Based on Medicinal Plants

For thousands of years, people have prized medicinal plants as a rich source of therapeutic compounds for the treatment of a wide range of illnesses. Today, a sizable portion of the population suffers from kidney stones and urinary calculi. Stone illness has increased in incidence due to changes in lifestyle. The four main types of stones that form in the kidneysare calcium stones (75 to 85%), struvite stones (2 to 15%), uric acid stones (6 to 10%) and cystine stones (1 to 2%). The most common stone recorded in India is Calcium oxalate Kidney stones. Surgical treatment of the kidney stone is expensive and may result into reoccurance also. Since Herbal Plants are safer, more efficient, more acceptable culturallyand have fewer side effects than produced pharmaceuticals. Medicinal herbs have been used for treatment of kidney stone for millennia. Patients are recommended to follow a low-fat diet and take herbal remedies in addition to fibre from naturally occurring plants. Antiurolithiatic Herbs are used to treat Kidney Stones. The purpose of this article is to review the different types, diagnostic methods, ancient treatment of kidney stone and to emphasize the use of medicinal herbs for the treatment for Kidney Stones.

Effect of silica fume on the performance of high-early-strength UHPC prepared with magnesium ammonium phosphate cement

Although ultra-high performance concrete (UHPC) prepared from Portland cement has high long-term strength and durability, its early strength development is still can be enhanced for shortening the prefabrication period or using it as a rapid repair material. Therefore, magnesium ammonium phosphate cement ultra-high performance concrete (MAPC-UHPC) was prepared using magnesium ammonium phosphate cement (MAPC), sand, steel fiber, and silica fume (SF) in this study. The effects of replacing MAPC with SF (5%–15%) on the fluidity, strength, and microstructure of MAPC-UHPC were studied. The results showed that the spread diameter of the MAPC-UHPC mixture was greater than 200 mm, and the setting time was between 5.5 and 8.5 min. Meanwhile, the 6-h compressive strength of MAPC-UHPC was higher than 100 MPa and could reach about 140 MPa in 28 d. When the 5%–15% binder was replaced by SF, the MAPC-UHPC fluidity and setting time increased with the increase in SF content. When 5% SF was used, the 6-h and 28-d compressive strengths of MAPC-UHPC increased by 3.91% and 3.86%, respectively, compared with the plain sample. The addition of SF promoted the formation of struvite and refined the pore structure, which also increased the compactness of the microstructure.

Current Practices and Challenges in the Management of Complex Renal Stones in Africa: A Scoping Review.

This study reviews the challenges and management strategies for complex renal stones in Africa. Historically viewed as infection or struvite stones, recent studies highlight diverse compositions of staghorn stones. These complex stones pose significant risks, including recurrent urinary tract infections and renal impairment. In the past, conservative management of staghorn stones was associated with high morbidity; thus, surgical intervention was necessary for complete eradication. While percutaneous nephrolithotomy (PCNL) remains the standard, it carries notable risks, leading to a shift towards minimally invasive techniques. This study reviews challenges and management practices for complex renal stones and staghorn calculi in African countries, evaluating stone-free rates and associated complications. A scoping review of the literature, following the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, was performed. A systematic search was conducted in PubMed, African Journal Online (AJOL)and Google Scholar, yielding 1,101 articles, but only 11 articles satisfied the inclusion criteria. The study included 1,513 patients with 1,582 renal units, predominantly male (67.2%) with an average age of 40.7 years. Percutaneous nephrolithotomy (PCNL) was the primary treatment for the majority (71.3%), followed by open surgery (21.9%), laparoscopic surgery (4.1%), and retrograde intrarenal surgery (RIRS) (2.7%). The stone clearance rates for PCNL, open surgery, laparoscopic pyelolithotomy, and RIRS were 82.8%, 83.7%, 100%, and 92.8%, respectively. Stone sizes ranged between 22 and 80 mm, with 66% being staghorn stones. Complication rates were highest for open surgery (30.8%) and lowest for RIRS (4.7%). Despite PCNL being the global standard, African studies still indicate a high reliance on open surgery, likely due to healthcare infrastructure, resource availabilityand socioeconomic factors. Enhancing access to urological care and addressing healthcare disparities are imperative for improving staghorn stone management in Africa.

#2228 Hypocitraturia is the main factor associated with proteinuria in patients with kidney stones

Abstract Background and Aims Patients with kidney stones (KS) are at increased risk for chronic kidney disease. Research published so far has focused on factors associated with low glomerular filtration rate in KS patients, however, factors associated with proteinuria have not been fully described. The aim of this retrospective study was to assess the presence of proteinuria in our cohort of patients with known or presumed calcium KS and to analyze which common clinical and metabolic variables might be associated with proteinuria. Method We performed a retrospective cross-sectional study in patients (pts) treated at our stone clinic at the University Medical Centre Ljubljana in the ten-year period from January 1st 2010 to December 31st 2019. We excluded patients who did not have 24-hour proteinuria determined and patients with known urate, struvite or cystine stones. We noted the presence of arterial hypertension (AH), diabetes mellitus, a family history of kidney stones, age, sex, eGFR, body mass index, history of renal colic events and urological procedures for kidney stones, and 24-hour urine measurements (calcium, urate, oxalate, citrate, sodium, and proteinuria). Categorical variables were analyzed with Chi-Square test, normally distributed numerical values with Student's t-test and non-normally distributed with Mann-Whitney U test. P-values < 0.05 were considered statistically significant. Associations with p-values < 0.1 were included into a binary logistic regression analysis to determine the probability of predicting the presence of 24-hour proteinuria, defined as > 0.25 g/day in our laboratory. Results In the allocated time period 335 pts were examined. After exclusion, 251 pts were included into the analysis (mean age 49.5 ± 14.2 years, 116 (46.2%) males, 135 (53.8%) females). Complete 24-hour urine metabolic analysis was available for 238 pts. Proteinuria was present in 40 pts (15.9%) and was significantly more common in pts with AH compared to normotensive pts (18/77 (23.4%) vs. 22/174 (12.6%), p 0.027) and more common in males compared to females (23/116 (19.8%) vs. 17/135 (12.6%), p 0.083). Numerical variables with a p-value < 0.1 regarding the association with the presence of proteinuria are presented in Table 1. In regression analysis the model significantly predicted the presence of proteinuria (χ2 20.738, p 0.014, R2 0.343) and was able to predict the result overall in 85.2% of cases. Of all the variables included only citrate significantly predicted the presence of proteinuria (OR 1.732; 95% CI 1.009, 2.972; p 0.046). Proteinuria was significantly more common in pts with hypocitraturia (<1.67 mmol/day) compared to pts with normal urinary citrate (29/116 (25%) vs. 9/122 (7.4%), p < 0.001) and in pts with immeasurably low urinary citrate (<0.2 mmol/day) compared to higher citrate (15/27 (55.6%) vs. 23/211 (10.9%), p < 0.001). Conclusion Proteinuria was relatively common in our cohort. The main factor associated with proteinuria was urinary citrate. Proteinuria was significantly more common in pts with hypocitraturia compared to pts with normal urinary citrate and was present in the majority of pts with immeasurably low urinary citrate. Further studies are warranted to clarify the clinical relevance and implications of this findings.

Kidney stone growth through the lens of Raman mapping

Bulk composition of kidney stones, often analyzed with infrared spectroscopy, plays an essential role in determining the course of treatment for kidney stone disease. Though bulk analysis of kidney stones can hint at the general causes of stone formation, it is necessary to understand kidney stone microstructure to further advance potential treatments that rely on in vivo dissolution of stones rather than surgery. The utility of Raman microscopy is demonstrated for the purpose of studying kidney stone microstructure with chemical maps at ≤ 1 µm scales collected for calcium oxalate, calcium phosphate, uric acid, and struvite stones. Observed microstructures are discussed with respect to kidney stone growth and dissolution with emphasis placed on < 5 µm features that would be difficult to identify using alternative techniques including micro computed tomography. These features include thin concentric rings of calcium oxalate monohydrate within uric acid stones and increased frequency of calcium oxalate crystals within regions of elongated crystal growth in a brushite stone. We relate these observations to potential concerns of clinical significance including dissolution of uric acid by raising urine pH and the higher rates of brushite stone recurrence compared to other non-infectious kidney stones.

Exploring the association between multiple factors and urolithiasis: A retrospective study and Mendelian randomization analysis.

To investigate the relationship between several factors and urinary stone as well as different stone compositions. To guide the diagnosis, treatment, and prevention of urinary stone recurrence. We used bidirectional Mendelian randomization to analyze the causal relationship between hypertension and urinary stones, diabetes and urinary stones, and body mass index (BMI) and urinary stones. We retrospectively analyzed the medical records of patients with urinary stones admitted to a tertiary care hospital in Chongqing, China, from July 2015 to October 2022. Patients were included when they were first diagnosed with urinary stones. The odds ratio of calculi on hypertension estimated by inverse variance weighted was 8.46 (95%CI: 4.00-17.90, P = 2.25 × 10-8). The stone composition analysis showed that there were 3101 (67.02%) mixed, 1322 (28.57%) calcium oxalate monohydrate, 148 (3.20%) anhydrous uric acid, 16 (0.35%) magnesium ammonium phosphate hexahydrate, 11 (0.24%) dicalcium phosphate dihydrate, 10 (0.22%) carbonate apatite, 8 (0.17%) L-cystine, 4 ammonium uric acid (0.09%), and 7 other stone types (0.15%). Mendelian randomization studies have proven that urinary stones may be a potential risk factor for hypertension, while there is no causal relationship between diabetes and stones, BMI, and stones. Our retrospective study has shown that urinary stone components are closely associated with sex, age, hypertension, diabetes, and BMI. It is reasonable to suspect that treating a single stone component is ineffective in preventing recurrence. We also found that the peak incidence of urinary stones was at the most active stage of most people's working lives.

Composition analysis of 1,495 cases of upper urinary tract calculi: the role of age and gender.

This study aimed to quantitatively analyze the calculi components of upper urinary tract calculi and to explore the relationship between calculus components, demographic characteristics, and underlying diseases. Clinical data of 1,495 patients with upper urinary tract calculi were retrospectively collected. The calculi were divided into simple calcium oxalate, calcium oxalate mixed, calcium phosphate mixed, uric acid, magnesium ammonium phosphate, and other components. Statistical software SPSS 22.0 was used to analyze the differences between the stone compositions and various factors. The influencing factors (p < 0.05) were analyzed using multiple logistic regression analysis. Among 1,495 patients with upper urinary tract calculi, simple calcium oxalate calculi were the most common component (39.7%), followed by calcium oxalate mixed calculi (30.4%), uric acid calculi (13.6%), calcium phosphate mixed calculi (10.4%), magnesium ammonium phosphate calculi (5.8%) and other component calculi (0.1%). Univariate analysis revealed statistically significant differences in stone composition according to gender, age, and hyperuricemia (p < 0.05). Multiple logistic regression analysis showed that compared to men, the odds ratio (OR) values of calcium oxalate mixed stones, calcium phosphate mixed stones, and magnesium ammonium phosphate stones in women were 1.61, 2.50, and 4.17, respectively (p < 0.001). Compared with elderly patients, the OR values of calcium phosphate mixed stones in young and middle-aged patients were 3.14 and 2.70, respectively (p < 0.05). Patients with different stone components had different demographic characteristics, and stone components were significantly different between gender and age. Calcium oxalate mixed stones were more common in females, and calcium phosphate mixed stones and magnesium ammonium phosphate stones were more common in females, young patients, and middle-aged patients.

Coupling of struvite crystallization and aqueous phase recirculation for hydrochar upgrading and nitrogen recovery during hydrothermal carbonization of sewage sludge

Recycling of aqueous phase (AP) as a by-product after hydrothermal carbonization (HTC) of sewage sludge (SS) has been of interest. The combination of magnesium ammonium phosphate (MAP) or the so-called struvite crystallization and aqueous phase (AP) recirculation has great potential for resource recovery and hydrochar enhancement. In this study, both the aqueous phase of HTC after MAP recovery of NH4+-N (AP-MAP) and the untreated aqueous phase of HTC (AP-HTC) were reused for HTC of fresh SS, and both aqueous phases were recycled four times. The effects of the two AP cycles on the properties of AP and hydrochar at 200, 230, and 260 °C were studied, and the effect of temperature on the two AP cycles was similar. The hydrochar produced by the AP-MAP cycle had lower nitrogen content than that of the AP-HTC cycle due to the low ammonia nitrogen (NH4+-N) content, and the combustion performance was improved. MAP recovery reduces the accumulation of NH4+-N in the AP cycle and MAP is also a high-quality fertilizer. Therefore, the combination of MAP recovery and AP recycling provides a feasible technical approach for resource utilization, eutrophic AP treatment, and production of high-quality hydrochar in the HTC process of SS.

Cell death‑related molecules and targets in the progression of urolithiasis (Review).

Urolithiasis is a high‑incidence disease caused by calcium oxalate (mainly), uric acid, calcium phosphate, struvite, apatite, cystine and other stones. The development of kidney stones is closely related to renal tubule cell damage and crystal adhesion and aggregation. Cell death, comprising the core steps of cell damage, can be classified into various types (i.e., apoptosis, ferroptosis, necroptosis and pyroptosis). Different crystal types, concentrations, morphologies and sizes cause tubular cell damage via the regulation of different forms of cell death. Oxidative stress caused by high oxalate or crystal concentrations is considered to be a precursor to a variety of types of cell death. In addition, complex crosstalk exists among numerous signaling pathways and their key molecules in various types of cell death. Urolithiasis is considered a metabolic disorder, and tricarboxylic acid cycle‑related molecules, such as citrate and succinate, are closely related to cell death and the inhibition of stone development. However, a literature review of the associations between kidney stone development, metabolism and various types of cell death is currently lacking, at least to the best of our knowledge. Thus, the present review summarizes the major advances in the understanding of regulated cell death and urolithiasis progression.

Etiology, pathogenesis, diagnosis and treatment of encrusted cystitis and pyelitis: Review of the problem from a historical perspective

Introduction: Encrusted cystitis and pyelitis share many similarities regarding etiology, pathogenesis, diagnosis and treatment. These processes usually occur on previously injured urological tissue with the participation of an infection by urease-producing bacteria. At present Corynebacterium urealyticum, a highly antibiotic-resistant bacteria, appears to be the pathogen most often involved in these processes. In this review we analyze the history of these diseases with special emphasis on the scientific advances of the last century. We also review the role of urease and bacterial infection as well as a brief update on the epidemiological, histopathological, diagnostic and therapeutic aspects. Relevance: The importance and severity of these pathologies that are frequently underdiagnosed and difficult to treat are stressed. Conclusions: The clinical history, exploratory and analytical data, which highlight alkaline urine, sometimes with an ammoniacal odor, pyuria, hematuria and the presence of magnesium ammonium phosphate crystals, should alert the urologist to the existence of an encrusting uropathy. Simple radiology, ultrasound, computed tomography and endoscopic visualization of the lesions confirm the diagnosis. Treatment generally requires surgery, use of antibiotics, urinary acidifiers and bacterial urease inhibitors. Keywords: cystitis, pyelitis, encrustations, infection

Wastewater-Derived Struvite has the Potential to Substitute for Soluble Phosphorus Fertiliser for Growth of Chickpea and Wheat

Phosphorus (P) recycling from wastewater can reduce the reliance on the primary source for P fertilisers―rock phosphate reserves. In light of this, we compared the effects of struvite (ST), a sparingly soluble P product derived from wastewater, and readily soluble KH2PO4 (KP) on chickpea (Cicer arietinum L.) and wheat (Triticum aestivum L.) growth and P acquisition. Plants were grown in a temperature-controlled glasshouse in plastic pots containing a soil mixture with low P availability, with ST or KP applied at five P rates (7, 14, 28, 56 and 112 µg P g− 1 dry soil). Plants were harvested 56 days after sowing when there were visible differences in above-ground growth. Chickpea and wheat growth positively responded to increasing P rates of KP and ST. At low and medium P rates (7, 14, 28 and 56 µg P g− 1 dry soil) of KP and ST, the plants acquired similar amounts of P, while at a higher P rate (112 µg P g− 1 dry soil), plants supplied with ST, accumulated 1.2- to ~ 2.0- fold higher P than KP. Rhizosheath soil pH increased by ~ 0.1–0.7 units under ST than KP for both species. Wheat produced greater total root length but lower amount of rhizosheath carboxylates than chickpea under KP and ST, and wheat accumulated more P than chickpea under KP and ST. Chickpea and wheat can well access P from ST, indicating the great potential of ST as an alternative P fertiliser.

Influences of reaction parameters and complexation pretreatments on the distribution of phosphorus during hydrothermal carbonization of dewatered sewage sludge

This study investigated the effects of reaction parameters and pretreatments with complexing agents, namely ethylenediaminetetraacetic acid (EDTA), glutamate diacetic acid (GLDA), and citric acid (CA), on the phosphorus contents and forms in the sludge hydrothermal carbonization products. The results showed that reaction temperature had the greatest effect on the distribution and forms of phosphorus in liquid and solid products. High reaction temperatures inhibited the transfer of phosphorus from the solid phase to the liquid phase. Indeed, the proportions of phosphorus in the liquid phases only accounted for 3.56 % at reaction temperature and time of 160 °C and 60 min, respectively. However, this proportion increased to 16.32, 12.62, and 13.15 % following complexation pretreatments with EDTA, GLDA, and CA at 0.1 mol/L, respectively. In addition, the complexation pretreatments enhanced the transfer of phosphorus from the solid phase to the liquid phase. The total phosphorus contents in the liquid phase (TPL) reached 896.46 mg/L. The finding can be explained by the binding of the complexing agents with metal ions, such as Mg, Ca, Al, and Fe, transferring phosphorus originally bound to these metal ions to the liquid phase. In addition, the results demonstrated the effectiveness of the magnesium ammonium phosphate (MAP) crystallization method for recovering phosphorus from the EDTA-pretreated liquid product. X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analyses showed high purity and crystallinity of the obtained struvite to some extent.

STRUVITE CRYSTAL UROLITHIASIS IN A 2 YEAR OLD CASTRATED MALE CAT

Urolithiasis, kidney failure, urinary tract infections are examples of disorders of the urinary tract that often become problems in cats. Urolithiasis is a medical term to describe the presence of stones or crystals known as “urolith” in the urinary tract. Inappropriate composition and feeding methods can cause nutritional imbalances in the cat's body, which can affect the acidity level (pH) of urine, urine volume and urine concentration which can cause the formation of excessive minerals in the urine. The aim of writing this article is to provide information regarding the treatment of crystal urolithiasis in local cats. A male cat named Goblin, has been castrated, has colored hair orange with body weight 5.3 kg, experiencing difficulty urinating since 3 weeks, excreting a small volume of urine, and blood in the urine. On physical examination the cat always curled up and felt pain when palpation was carried out abdominal part. The results of the cat's blood test showed leukocytosis, lymphocytosis, thrombocytopenia, and RDW CV increased and PCT decreased. The results of the cat's urinalysis showed presence of leukocytes +2, Protein +1, pH 8.0, specific gravity 1.030, Calcium +1, Microalbumin +1.Sediment test results also found the presence of deposits of magnesium ammonium phosphate crystal particles (struvite crystals).Results of urine culture examination bacteria were foundStaphylococcus sp. Ultrasound results showed enlargement of the left kidney and deposits of hyperechoic particles (crystals) accompanied by enlargement of the uterine sac. The cat was diagnosed with urolithiasis with a fausta prognosis. The cat was treated by installing a 4Fr/1.3x130mm urinary catheter and flushing using 0.9% physiological NaCl to make it easier for the cat to urinate. The therapy given is the antibiotic ciprofloxacin hcl 5 mg/kg BW s500 mg preparation with a dose of 50 mg/kg BW per oral (PO) administered 2 times a day for seven days, administering the anti-inflammatory dexamethasone 0.5 mg with a dose of 1 mg/kg BW PO and given 2 times a day for four days, and kejibeling herbal medicine 1 tablet times a day for seven days. Cats are also given feed therapy in the form of Royal Canin Urinary S/O for 3 months. Evaluation of the cat's condition improved after therapy for 7 days. There is a need to educate clients regarding cat care, feeding and drinking water. Therefore, the cat's feed in cases must be replaced by providing urinary therapy feed.

Effect of fly ash and metakaolin on the mechanical properties and microstructure of magnesium ammonium phosphate cement paste

To solve the current application problems of magnesium phosphate cement (MPC), this study investigates the working properties, hydration process, strength performance, bonding strength, and other characteristics of MPC with 10% to 40% substitution of fly ash (FA) and metakaolin (MK) using different mixing methods. Among them, FA has beneficial effects such as spherical effect, microaggregate effect, and volcanic ash effect in the MPC system, and in addition, the aluminum phase material contained in MK has been shown to react with phosphates. This experimental design was aimed at determining the intrinsic link between bond strength and the aforementioned properties of MPC. The findings suggest that the optimal strength performance was achieved with an FA content of 20%, while the best bonding performance was observed at an FA content of 10%. There was minimal difference in peak hydration temperature among different MK admixtures, and no significant deviation was observed in the strength properties. The poor fluidity of the slurry hindered its penetration into the matrix, resulting in weak early bonding strength within the MK group. In the MK=5% mixing ratio of FA and MK (FK), FK-31 exhibited excellent strength performance with distinct advantages in terms of hydration product quantity and morphology, as well as remarkable macroscopic properties. On the other hand, in the MK=10%, FK-22 demonstrated outstanding performance utilizing the FK groups with strength comparable to FA-1 and FA-2. However, its toughness index-C/F decreased to a minimum level, which implied that the toughness of MPC was improved. Simultaneously, it displayed superior bonding properties surpassing MPC by reaching 5 MPa at 7d. The experimental group showed that excellent bonding properties mainly relied on chemical penetration as the bounding mechanism while interfacial damage primarily manifested as matrix damage. The microscopic tests showed that aluminum-containing phase substances were detected in the MK group, which made the equal substitution amount of MK show superior strength to FA. In this study, MK and FA were mixed in two ways: individual and composite mixing to investigate the modification effect of compounding of dopes with different chemical and physical properties and their bonding properties were analyzed. The test results indicated that under appropriate mixing proportions, incorporating both MK and FA for modified MPC could compensate for shortcomings associated with single mixing methods and become a novel option for modified MPC.

Magnesium source with function of slowly releasing Mg and pH control for impurity-resistance synthesis ultra-large struvite from wastewater

Struvite (MgNH4PO4·6H2O, Magnesium ammonium phosphate, MAP), recovered from wastewater, has potential application as a slow-release fertilizer. However, crystal size distribution (CSD) of recovered MAP typically lied in the range of 50–300 μm, due to fast nucleation rate and notably narrow metastable zone width (MSZW) of MAP, with purity levels 40–90 %. In order to control the rate of nucleation, a novel magnesium source with the form of MgHPO4·3H2O wrapped with Mg(OH)2 was prepared, referred to as P-3. This compound gradually released Mg2+ and PO43−, regulating solution concentration kept in MSZW to promote crystal growth. The inherent Mg(OH)2 within P-3 also acted as a pH regulator in wastewater, eliminating the necessity for additional acid or alkali adjustments during crystallization process. The MAP precipitated by P-3 exhibited an impressive CSD of 5000–7000 μm, with a maximum size reaching 10,000 μm. This represented the largest CSD reported in literature for recovered MAP from wastewater. The significance of the ultra-large MAP precipitated by P-3 lied in its enhanced resistance to impurity adsorption, resulting in MAP with a remarkable purity 97 %, under conditions of low heavy metal ion concentration approximately 5 mg/L. Furthermore, the removal efficiency of ammonia nitrogen (NH4+) can reach 92 %. In comparison, two other magnesium sources, soluble salts (MgCl2 and Na2HPO4, P-1) and a combination of insoluble salts (Mg(OH)2 and MgHPO4, P-2) were evaluated alongside P-3. The CSD of MAP precipitated from P-1, P-2 was both <100 μm, with purity levels of 90 and 92 % and NH4+ removal efficiency of 92 and 90 %, respectively. Importantly, the strategy of obtaining ultra-large size MAP from wastewater in this study provided novel insights into the crystallization of other insoluble salts with large sizes.

Composition analysis of renal and ureteral calculi in a single center in northern China in the past decade.

The current report aimed to evaluate the characteristics of stone composition in 3637 renal and ureteral calculi patients in a single center while clarifying its relationship with sex, age, and time. Out of 3637 cases of upper urinary tract stones, stone specimens were analyzed retrospectively. There were 2373 male patients aged 6 months-87 years, with an average age of 44.73 ± 15.63 years, and 1264 female patients aged 4 months-87 years, with an average age of 46.84 ± 16.00 years. The male-female ratio was 1.88:1. Five hundred twelve patients had ureteral calculi, and 3125 had renal calculi. The SPSS software helped analyze the relationship between renal and ureteral calculi composition and sex, age, and time. Stone composition demonstrated 2205 cases of calcium oxalate stones (60.6%), 518 carbonate apatite (14.2%), 386 uric acids (10.6%), 232 magnesium ammonium phosphate (6.4%), 117 calcium phosphate (3.2%), 76 cystine (2.1%), 47 sodium urate (1.3%), 31 others (0.9%), and 25 ammonium urate (0.7%) cases. The overall male-to-female sex ratio was 1.88:1. Stones in the upper urinary tract were significantly more frequent in men than in women between the ages of 31 and 60. However, such stones were significantly more frequent in women than men over 80 (P < .05). Cystine, Sodium urate, Carbonated apatite, and uric acid indicated significant differences between different age categories (all P < .001). Stone composition analyses revealed that the frequency of calcium oxalate calculi has increased annually, while cystine and carbonated apatite incidences have dropped annually over the past decade. The components of renal and ureteral calculi vary significantly based on age and sex, with calcium oxalate calculi being more frequent in men while magnesium ammonium phosphate stones are more frequent in female patients. The age between 31 and 60 years is the most prevalent for renal and ureteral calculi in men and women.

Characterisation and agronomic evaluation of acidified food waste anaerobic digestate products

Raw liquid anaerobic digestate was synthesised into nutrient-dense solid digestates via acidification and evaporation. Acidification retained ammonium in the digestate whilst also donating the anion to free ammonium to form an ammonium salt. Digestate was treated with the addition of sulphuric, nitric, and phosphoric acid resulting in the formation of ammonium sulphate, ammonium nitrate and ammonium phosphate, respectively then evaporated into a solid fertiliser product. FTIR, XRD and SEM-EDS collectively confirm that the addition of acids completely converted the free ammonium in the raw digestate into their respective ammonium salt counterparts. Compounds of potassium chloride, silicon dioxide, calcium carbonate, magnesium ammonium phosphate, sodium nitrate, and sodium chloride were identified in all solid digestate samples. Plant growth and grain yield was higher in urea ammonium nitrate, raw liquid digestate and acidified digestate products compared to control and unacidified solid digestate. Urea ammonium nitrate and ammonium nitrate solid digestate had the highest dry shoot, likely due to the high available nitrogen found in both fertilisers. Overall, acidification and evaporation of liquid digestate can efficiently transform it into a valuable solid fertiliser with a high nutrient density. This process not only has the potential to mitigate handling and storage constraints of low nutrient density digestate in anaerobic digestion facilities but also offers a sustainable alternative to conventional fertilisers.