Metal Fixation Research Articles

Assessment of mine tailings as precursors for alkali-activated materials for on-site applications

Year after year the mining industry generates 5–7 billion metric tons of tailings worldwide. They are mostly disposed rather than valorised. The substantial amounts of tailings has led to growing concerns about their ecological and environmental impacts such as occupation of large areas of land, generation of windblown dust, and contamination of surface and underground water. Over the past years the mining industry has been subjected to increase environmental principles. As the consequence, besides waste rock and water management, tailings management becomes a progressively important factor for ecologic and economic reasons.Mine tailings from flotation processes are normally disposed in impoundments on the surface. This may cause environmental and safety problems including serious water pollution arising from contamination of surface water, groundwater, and soils due to the leaching of heavy metals, process reagents, and Sulphur compounds. Recently the process of alkali-activation and geopolymerisation has been explored as a potential method for tailings consolidation and heavy metal fixation. The tailings of many existing mining operations contain the aluminosilicate minerals needed for alkali-activation at least to some extent. From a sustainability point of view it makes sense to use alkali-activated products from tailings directly on the mine site as e.g. (1) backfill material applied to fill open cavities from the (underground) mining operation and (2) cover materials for surface deposits of tailings in order to store them ecologically safe and sealed off from the environment.Mine tailings from different mining operations around the world have been investigated regarding their potential use as precursors for alkali-activated materials. An assessment of the release of gel forming elements into alkaline solutions was performed by leaching experiments under various conditions (time, concentration of the solvent, and temperature). Compared to traditional alkali-activated precursor materials the release of aluminium and silicon is in general low for the mine tailings investigated. However, results indicate a favourable ratio of Si/Al for the formation of gels similar to other alkali-activated products. Additionally, the leached calcium can contribute to the strength of the resulting products by forming C-S-H gels when a considerable amount of Si is present in the pore solution either from the activator or dissolved from the material itself.The results of the leaching tests were used to facilitate the mix design for alkali-activated products. In order to increase the mechanical strength of the final product different approaches were considered: (1) addition of reactive materials (e.g. blast furnace slag), (2) increasing the reactivity of the tailings by grinding, and (3) increasing the reactivity by curing at elevated temperature. Depending on the tailings type, the mix design, and the curing conditions the final material shows a compressive strength in excess of 30 MPa even for curing at low temperatures.The investigated mine tailings can potentially be used for various applications on the mine site. With regard to specific target applications a further evaluation of long term properties of the resulting products (e.g. freeze–thaw resistance) has to be performed. Furthermore, results indicate that products with even higher strength can be manufactured by further reducing the particle size of the tailings or by the addition of other reactive materials.

A comparative analysis of the surgical treatment of preschool children with congenital spinal deformation and isolated hemivertebra from the combined and dorsal approaches

Background. Currently, there are many studies on the evaluation of the results of surgical intervention and the comparative analysis of various surgical techniques for treating children with congenital spinal deformities. However, there is no consensus regarding the choice of surgical access to the abnormal vertebra that considers the duration of surgery, the volume of intraoperative blood loss, the degree of correction achieved during the intervention, the length of metal fixation, and the preservation of the result in the long-term observation period.
 Aim. The goal is to identify the advantages and disadvantages of the dorsal and combined approaches to the surgical treatment of preschool children with congenital deformities of the thoracic and lumbar spine against the background of an isolated violation of the vertebral formation.
 Materials and methods. A retrospective analysis of 56 patients under the age of five with congenital spinal deformities and a history of an isolated hemivertebra in the thoracic and lumbar regions who underwent one-stage hemivertebral extrusion from a dorsal approach (1st group: n = 30) or from a combined approach (2nd group: n = 26) was conducted.
 Results. All patients showed improvement in the sagittal and frontal profiles of the spine. However, during separation in the first group of patients, a progression of the kyphotic component of the deformity in the lumbar spine from 19 to 8 was noted, while the correction value of the curvature of the scoliotic component remained stable. Intraoperative blood loss in the first group of patients was less (234 mL) compared with that in the second group (319 mL), while the duration of surgery was longer (310 min and 185 min, respectively). On average, in the first group, a longer metal structure was used to correct the spinal deformity compared with the second group.
 Conclusions. The correction of the patients congenital spinal deformities with a single hemivertebra from a combined access approach allows a complete correction of the congenital curvature, the fixation of a smaller number of vertebrae, and the maintenance of a stable result in the long-term observation period compared with the dorsal approach. Isolated dorsal access to the hemivertebral body is characterized by less intraoperative blood loss compared with the combined approach, although the length of surgical intervention is increased.

Chemical fixation of toxic metals in stainless steel pickling residue by Na2S∙xH2O, FeSO4∙6H2O and phosphoric acid for beneficial uses

The leaching concentrations of different metals in stainless steel pickling residue (SSPR) were determined and the toxic metals were treated using Na2S∙xH2O, FeSO4∙6H2O, and phosphoric acid. A modified European Community Bureau of Reference (BCR) sequential extraction was used to identify the speciation of the concerned metals. Results showed that SSPR contains a large amount of Ca (58.41%), Fe (29.44%), Cr (3.83%), Ni (2.94%), Mn (2.82%) and some of Al, Cu, Mg, Zn. Among them, Cr and Ni were the most toxic metals in SSPR, thus the raw SSPR falls into hazardous waste category due to the leaching amount of Cr. In addition, the leached Cr was identified as Cr6+ (MgCrO4) in the waste. BCR test revealed that risk assessment code (RAC) of Cr and Ni were 33.29% and 61.7%, indicating they posed “high” and “very high” risk to the environment, respectively. After fixing by Na2S∙xH2O and FeSO4∙6H2O, the leaching concentrations of Cr and Ni were less than 1.5 and 0.5 mg/L, respectively. After fixing by Na2S∙xH2O and FeSO4∙6H2O the treated SSPR can be safely reused as roadbed materials, concrete and cement aggregates. This study provides a useful implication in treatment and beneficial reuse of heavy metal-containing hazardous wastes.

Biomechanical Characteristics of Metal Plate Fixators and Composite Plate Fixators

Biomedical properties of Metal Plate fixators and Composite fixators were carries out. Fatigue of the metal and composite materials were carried out, Dynamic mechanical analysis, Shear strength and tensile strength of the composite materials were also carried out. Finite element analysis of the plate fixator was carried out it. The results shows metal fixators are rigid and their strength is more than the bone, whereas composite materials can be tailor made to the need. Delamination occurs in composite materials.

Quantifying near metal visibility using dual energy computed tomography and iterative metal artifact reduction in a fracture phantom

PurposeTo quantitatively assess CT image quality and fracture visibility using virtual monochromatic imaging and iterative metal artifact reduction (iMAR) in a femoral bone fracture phantom with different fixation implants. MethodsA custom made phantom was scanned at 120-kVp and 140-kVp single-energy and 100/150-kVp dual-energy. Three stainless steel and two titanium implants with different thicknesses were placed on the phantom containing simulated one and two mm fractures. Single-energy CT images were reconstructed with and without iMAR, while DECT images were reconstructed at monochromatic energies between 70 and 190 keV. Non-metal scans were used as a reference. A Fourier power spectrum method and fracture model were used to analyze several anatomical areas. ResultsCT-value deviations of titanium implants were much lower compared to stainless steel implants. These deviations decreased for both DECT and iMAR. Fracture visibility, measured with the fracture model, improved the most when DECT was used while artifact reduction benefitted more from iMAR. The optimal monochromatic energy for metal artifact reduction, based on CT-value deviation, varied for each metal between 130 and 150 keV. The fracture model provided a signal-to-noise ratio for the near metal fracture visibility, providing the optimal keV. ConclusioniMAR and high keV monochromatic images extracted from DECT both reduce metal artifacts caused by different metal fixation implants. Quantitative femoral phantom results show that DECT is superior to iMAR regarding fracture visualization adjacent to metal fixation implants. The introduction of new artifacts when using iMAR impedes its value in near metal fixation implant imaging.

The Strength characteristics of Chitosan- and Titanium- Poly (L-lactic) Acid Based Composites

The problem of bone fracture and the need to avoid revision surgery in osteosynthesis are the critical reasons for the gradual shift from the use of metallic fixations to the polymeric scaffold in the orthopaedic applications. However, the mechanical properties of polymers that have become a substitute for metals need to be improved upon. An attempt was made to improve the mechanical properties of poly(L-lactic) acid (PLLA), a biopolymer, by loading it with 1.04, 2.08, 4.17, 8.33 and 16.67 wt.% of chitosan (an organic filler) and Ti-6Al-2Sn-2Mo-2Cr-0.25Si (an inorganic particle). Melt blend technique was the processing technique. Hardness, compressive modulus and fracture toughness of virgin PLLA improved significantly while the resulting composites were found to be less ductile than unreinforced PLLA. Titanium reinforced PLLA displayed superior mechanical properties over the neat and chitin reinforced PLLA. Compressive modulus values of the developed composites were much lower than the modulus of cortical bone, they were, however, mechanically compatible with the properties of cancellous bone. Optical microscopy images also show the formation of pores which are a catalyst for cell proliferation and cell differentiation.

Analysis of the accumulation and distribution of heavy metals in the soil cover of Samara and Syzran

The paper presents the results of a statistical analysis of the data on the accumulation and distribution of a number of heavy metals (Cr, Ni, Cu, Pb, Cd, Zn) in the soils of the cities of Samara and Syzran in the Samara Region, carried out using the Spearmans rank correlation coefficient, the Kruskal-Wallis one-way analysis of variance and principal component analysis. The authors show that the soils of Samara are more susceptible to the accumulation of Cr, Ni, Cu and Cd than the soils of Syzran. Higher gross concentrations of metals are observed in the functional zones of the cities characterized by increased technogenic load near industrial enterprises and along railways. The fixation of metals in the upper humus horizon is facilitated by the organic matter of the soil. The exception is Pb, whose total concentration does not depend on the type of functional zone and the content of organic carbon. The Kruskal-Wallis one-way analysis of variance made it possible to establish the presence of a statistically significant relationship between the mechanical composition of the soil and the gross concentrations of Cr and Ni, the content of which increases in soils of heavier texture. According to the principal component analysis, natural and technogenic sources of metals have a decisive influence on the content and distribution of heavy metals in the soil cover of the cities; soil characteristics (mechanical composition, actual acidity of the soil solution, organic carbon content) and the intensity of exposure to sources of heavy metals play a less significant role.

Synthesis of minerals and polymineral matrixes for immobilization of radioactive wastes elements

For the development of methods for the disposal of radioactive waste in the rocks of the earths crust, the concept of phase and chemical correspondence in the system of matrix material ― host rock has been proposed. This principle allows directional synthesis of certain mineral matrices. Matrix materials were experimentally synthesized ― solid solutions of minerals for immobilization of alkaline, alkaline-earth, rare-earth elements ― radionuclides. The properties of a number of solid solutions of minerals are investigated. The possibilities of processing graphite into stable matrices are studied. Methods of fixation and separation of noble metals (components of radioactive waste) and halides (Br, I) have been developed. The problems of processing glass matrix minerals (borosilicate and aluminophosphate glasses) into stable crystalline matrix materials are considered. Methods for processing glass matrices into mineral matrix materials are presented.

Temperature influence on mobilisation and (re)fixation of trace elements and heavy metals in column tests with aquifer sediments from 10 to 70 °C

The operation of seasonal underground thermal energy storages (UTES) as part of renewed heat supply systems can cause amplified temperature variations in the urban subsurface. Therefore, long-term environmental consequences for water extractions by trace elements and heavy metals (TEHMs) are a key point of concern regarding temperature effects on aquifer hydrogeochemistry. To address this issue, we report the results of flow-through and circular-flow column tests conducted with 4 anoxic northern German aquifer sediments, tempered to 10, 25, 40 and 70 °C and analysed for 20 TEHMs. Increased temperatures in column tests caused increasing Li, As, Mo, Sb and Ba concentrations and decreasing Ni concentrations in all of the sediments with a sediment-specific extent, whereas effects on V, Mn, Co, Tl and U concentrations varied sediment-specifically. Apart from Ba, all these components were released as a pulse in the initial heating phase, indicating a temperature dependent, finite, elutable pool. Re-cooling of the previously heated circular-flow column tests to 10 °C caused reversals of concentration changes by 30–95%. This indicates a return to initial hydrochemical conditions after termination of heat storage operation and downstream from heat storages during the operations. The latter was approximated for As with a simplified analytical 1-dimensional approach, presuming transferability from a laboratory to a field scale. This reversal in concentration changes enables active cooling as a countermeasure in cases of unexpected, adverse TEHM progression. From the perspective of our findings, TEHM concentration changes appear to be temporally and spatially limited.

Arthroscopic Reduction and Suture Bridge Fixation of a Large Displaced Greater Tuberosity Fracture of the Humerus

Arthroscopic fixation of a greater tuberosity (GT) avulsion fracture by suture bridge repair has been described in several articles. However, all of them have used arthroscopic fixation of a small sized GT fracture fragment or have not used purely arthroscopic techniques. In this Technical Note, the authors describe another technique for large displaced GT fracture fixation by arthroscopy only, without any metal fixation. Standard anterior, posterior, lateral, and posterolateral viewing portals are established with an accessory portal for suture anchor insertion. During intra-articular examination, an anteroinferior capsulolabral tear, upper one-third subscapularis tendon tear, and posterosuperior displaced bony fragment are detected. A subscapularis tendon was repaired by a single-row technique. After repair, medial row anchors are inserted into the bare area of infraspinatus tendon and the posterior edge of supraspinatus tendon. A 1-PDS suture is used to pass strands of fiberwire. As with the remplissage procedure, the fiberwire was passed with an 18-gauge needle. Following the acromioplasty, the medial row tightening was done by reducing the fracture fragment. After that, the lateral row anchor was inserted into the bicipital groove, completing the suture bridge technique. This technique can effectively treat other pathologies, has less radiation hazard, and results in fewer soft tissue injuries.

A Comparative Study of Cement-Bentonite and Cement-Based Remediation of Lead-Contaminated Soils

The mixture of bentonite and cement at a mass ratio of 2:1 (recorded as BC) was used as solidifying agent to repair lead contaminated soil, and traditional cement (PC) was used as contrast solidifying agent. The comparative test results show that the soil restoration and maintenance period reach 7 days and 28 days respectively. Compared with PC solidified soil, the pH and EC value of BC solidified soil is lower, and the pH value and EC value of 4% and 8% BC-solidified soil meet the interval value needed for vegetation growth. The dissolution of heavy metals in BC-solidified soil and PC-solidified soil decreases with the increase of the content of solidifying agent. At the same content, the dissolution of heavy metals in BC-solidified soil is lower, which indicates that the mixed material (bentonite + cement) has better effect on the fixation of heavy metals. The unconfined compressive strength of BC-solidified soil and PC-solidified soil increases with the increase of the content of solidifying agent, but compared with PC-solidified soil, the unconfined compressive strength of BC-solidified soil decreases significantly. Lower unconfined compressive strength is beneficial to the secondary development and utilization of solidified soil. The above research results show that the mixed material of bentonite and cement can effectively fix the heavy metal lead in the soil, avoid the excessive strength of the soil, and consequently cause soil hardening and influence the re-development and utilization. The mixed material is a feasible and economical repair material.

Serum Metal Levels in Maxillofacial Reconstructive Surgery Patients

The aim of this pilot study was to assay metal concentrations in the serum of patients who had undergone dental implant placement, orthognathic surgery using rigid metal fixation plates and screws and total temporomandibular joint replacement.

Desorption of Heavy Metals from Lime-Stabilized Arid-Soils using Different Extractants

This article evaluates the desorption of heavy metals from lime-stabilized, contaminated semi-arid soils under harsh environmental conditions involving chemical extractants, specifically, acetic acid (CH3COOH), nitric acid (HNO3), ethylene diamine tetra-acetic acid (EDTA), and diethylene triamine penta-acetic acid (DTPA). In this study, heavy metals, such as arsenic (As), chromium (Cr), mercury (Hg), and lead (Pb), were spiked with two semi-arid soils (exhibiting different plasticity characteristics) at different load ratios (10–250 mg/kg); they were later stabilized with lime to evaluate the reduction in their mobility. Extensive desorption tests were performed on these soil mixtures to study the efficacy of lime for the in situ fixation of heavy metals. This study revealed that irrespective of the nature and size of the heavy metal, the removal efficiency for the soils was greater than 80%, and EDTA at a concentration of 1 M yielded the maximum removal efficiency. It was found that the cationic metal ions Hg and Pb were desorbed effectively by EDTA, while As was desorbed by HNO3 and Cr by DTPA. The order of desorption for heavy metals was found to be as follows: As > Cr > Hg > Pb. The lime amended soils exhibited lower removal efficiencies (more than 48% retained) due to efficient retention of metals in the soil interstices, making them inert and immobile. There was an improvement of 40% in soils amended with lime compared with virgin soils in the case where soil washing by harsh washing agents was resisted; this proves that the contaminants were embedded in the interstices of the soil calcium interfaces. Therefore, this study asserts the notion that the mobility of heavy metal ions from brownfields can be effectively reduced by in situ lime treatment.

Authors’ response to critical comments: High tibial osteotomy with modern PEEK implants is safe and leads to lower hardware removal rates when compared to conventional metal fixation: a multi-center comparison study

Authors’ response to critical comments: High tibial osteotomy with modern PEEK implants is safe and leads to lower hardware removal rates when compared to conventional metal fixation: a multi-center comparison study

Critical comments to the publication “Hevesi M, Macalena JA, Wu IT, Camp CL, Levy BA, Arendt EA, et al. (2018) High tibial osteotomy with modern PEEK implants is safe and leads to lower hardware removal rates when compared to conventional metal fixation: a multi-center comparison study. Knee Surgery, Sports Traumatology, Arthroscopy 1–11”

Critical comments to the publication “Hevesi M, Macalena JA, Wu IT, Camp CL, Levy BA, Arendt EA, et al. (2018) High tibial osteotomy with modern PEEK implants is safe and leads to lower hardware removal rates when compared to conventional metal fixation: a multi-center comparison study. Knee Surgery, Sports Traumatology, Arthroscopy 1–11”

Остеомиелитические полости, как форма хронического остеомиелита, с точки зрения рентгеноморфологии

Introduction Osteomyelitic cavity is one of manifestations of chronic osteomyelitis (cOM) that requires continuous application of both non-operative and surgical interventions. The condition is often recurrent. The study of bone quality, techniques for identifying boundaries of pathological process should contribute to the development of advanced methods of treatment to avoid recurrence. Material and methods Radiomorphological assessment of the femur and tibia was performed for 48 patients with cOM characterized by osteomyelitic cavities using polypositional radiology and multislice computed tomography (MSCT) and quantification of bone density produced at the cavity and throughout the bone. Results Review of MSCT findings showed involvement through the cortical bone thickness of osteomyelitic cavity, structural changes in the entire bone with sinuses, sequestrae and alterations in the soft tissues (n = 40). Cortical bone was entirely involved in the cavity, with sinus observed and half-length of the bone featured with normal structure and low density in five patients. COM was diagnosed with present fixation metal constructs (n = 2) and recurrence noted after cavity repair with osteoinductive material (n = 1). Conclusion The findings showed that osteomyelitic cavity in patients with cOM resulted in extensive disorders of bone structure and density, evident changes in cortical bone, multiple layers, defects, considerable density fluctuations in intramedullary canal, in particular.

Effects of natural zeolites on ryegrass growth and bioavailability of Cd, Ni, Pb, and Zn in an Albanian contaminated soil

The use of eco-friendly and cost-effective adsorbent materials in the remediation of soils contaminated by potentially toxic elements (PTE) is a sustainable way of reducing the transfer of these elements into the food chain. However, an evaluation of the potential of natural zeolites to immobilize toxic elements in contaminated soils was required to enable their efficient use. The effect of natural zeolite (Stilbite-Stellerite) from the Munella area (Northern Albania), added at rates ranging from 1.25 to 10 % w/w on a contaminated soil was investigated in a greenhouse pot experiment with ryegrass (Lolium multiflorum L.) and by selective extractions. PTE availability for plants was assessed either as their accumulation in plant tissue or by DTPA-extraction. Oral bio-accessibility was estimated by the in vitro PBET method and the mobility and consequent potential risk of leaching by the USEPA TLCP method. The effect of zeolites on soil properties (pH, electrical conductivity-EC, organic C, and total N) was also investigated. A five steps sequential extraction procedure (SEP) was applied to investigate the immobilization mechanism. The addition of 2.5% w/w of natural zeolites caused a significant decrease of PTE mobility, but to observe a significant reduction of DTPA-extractable metals, it was necessary to reach 10% addition rate. In contrast, plant growth showed a gradual increase with addition rate and a corresponding decrease of concentration of PTE in plant tissue. Correlation between DTPA-extractable PTE and their concentration in both root and shoot plant tissue was rather poor. Human hazard due to soil ingestion (PBET method) changed only for Cu and Zn in the gastric phase with 1.25 and 5% addition rate respectively, whereas decreased for Cu and Zn at 5% rate in the Intestinal phase. The results of SEP support the hypothesis that the main mechanism involved in metals fixation are as follows: (1) insolubilization by pH rise, (2) adsorption on Fe/Mn oxides (3) increase of cation exchange retention, (4) organic complexation. The results of this work suggest that the addition of natural zeolites from the Munella area (AL) is a sustainable practice to reduce the environmental impact of PTE contaminated soils, but an assessment on the longevity of their immobilization need to be evaluated in the long-term perspectives.

Known-Component Model-Based Material Decomposition for Dual Energy Imaging of Bone Compositions in the Presence of Metal Implant.

Dual energy computed tomography (DE CT) is a promising technology for the assessment of bone compositions. One of potential applications involves evaluations of fracture healing using longitudinal measurements of callus mineralization. However, imaging of fractures is often challenged by the presence of metal fixation hardware. In this work, we report on a new simultaneous DE reconstruction-decomposition algorithm that integrates the previously introduced Model-Based Material Decomposition (MBMD) with a Known-Component (KC) framework to mitigate metal artifacts. The algorithm was applied to the DE data obtained on a dedicated extremity cone-beam CT (CBCT) with capability for weight-bearing imaging. To acquire DE projections in a single gantry rotation, we exploited a unique multisource design of the system, where three X-ray sources were mounted parallel to the axis of rotation. The central source provided high energy (HE) data at 120 kVp, while the two remaining sources were operated at a low energy (LE) of 60 kVp. This novel acquisition trajectory further motivates the use of MBMD to accommodate this complex DE sampling pattern. The algorithm was validated in a simulation study using a digital extremity phantom. The phantom consisted of a water background with an insert containing varying concentrations of calcium (50 - 175 mg/mL). Two configurations of titanium implants were considered: a fixation plate and an intramedullary nail. The accuracy of calcium-water decompositions obtained with the proposed KC-MBMD algorithm was compared to MBMD without metal component model. Metal artifacts were almost completely removed by KC-MBMD. Relative absolute errors of calcium concentration in the vicinity of metal were 6% - 31% for KC-MBMD (depending on the calcium insert and implant configuration), compared favorably to 48% - 273% for MBMD. Moreover, accuracy of concentration estimates for KC-MBMD in the presence of metal implant approached that of MBMD in a configuration without implant (6%-23%). The proposed algorithm achieved accurate DE material decomposition in the presence of metal implants using a non-conventional, axial multisource DE acquisition pattern.

Carboxylation as an effective approach to improve the adsorption performance of graphene materials for Cu2+ removal

Graphene materials are high-performance adsorbents for water and soil remediation, whose oxygen containing groups bind to metal ions intensely. In this study, we prepared carboxylated graphene oxide (GO-OCH2COOH) sponge and investigated the adsorption behaviors of Cu2+ on it by both experimental and computational approaches. Carboxylation largely improved the adsorption capacity from 23.8mg/g for graphene oxide (GO) sponge to 93.8mg/g for GO-OCH2COOH. The efficient adsorption was due to the strong interaction between Cu2+ and carboxyl groups (especially in –OCH2COOH form) according to the density functional theory calculation, while epoxy and hydroxyl groups contributed lowly. The fast adsorption process was achieved within 30min, corresponding to a large k2 value of pseudo-second order model (0.061mg/g/min). The adsorption was spontaneous and exothermic according to thermodynamics analyses. The binding strength of Cu2+ on GO-OCH2COOH was so strong that pH and ionic strength had mild impact. The strong binding sites were not recyclable, but the weaker ones (more than 40%) could be regenerated by simple washing. Our results highlighted the importance of chemical design in graphene adsorbents and the potential of GO-OCH2COOH in heavy metal fixation from water and soil.

Glycine transformation induces repartition of cadmium and lead in soil constituents

Heavy metal stress in soil accelerates the plant root exudation of organic ligands. The degradation of exudate ligands can be fundamental to controlling the complexation of heavy metals. However, this process remains poorly understood. Here, we investigated the relationship between the transformation of glycine, a representative amino acid exudate, and cadmium/lead mobility in soils. Two 48-h incubation experiments were conducted after glycine addition to the soils. Parameters related to glycine distribution and degradation, Cd/Pb mobility, and the formation of glycine-Cd complex were analyzed. Glycine addition gradually decreased the Cd and Pb mobility throughout the 48-h incubation. By the end of the experiment, the CaCl2-extracted Cd and Pb concentrations decreased by 63.5% and 43.6%, respectively. The glycine mineralization was strong in the first 6 h, as indicated by a sharp decrease in CO2 efflux rates from 10.04 ± 0.62 to 3.51 ± 0.07 mg C–CO2 kg−1 soil h−1. The mineralization rates notably decreased after 6 h. The comparisons of dissolved organic carbon and hydrolyzable amino acid contents indicated that glycine mineralization in solution (95.6%) was much stronger than that in soil solids (49.3%). At the end of incubation, 0.22 mmol kg−1 glycine remained in soil solids. The remaining glycine provided sufficient sorption sites for Cd2+ and Pb2+, resulting in enhanced metal fixation via complexation. Comparisons of zeta potentials supported the formation of the glycine-Cd complex. The Cd and Pb immobilization processes could be attributed to metal-glycine complex formation, sorption re-equilibrium, and glycine degradation. These findings emphasize that the biogeochemical processes of glycine, derived from root exudates or protein degradation products, increased the sorption of heavy metals to soils and thus reduced their toxicity to plants.